TWI223062B - Manufacture of an array pH sensor and device of its readout circuit - Google Patents

Abstract

In this invention, an extended gate ion sensitive field effect transistor (EGFET) was used to be an array pH sensor and its readout circuit. The multi-structures of this EGFET, which used to be an array pH sensor, are SnO2/A1/SiO2 gate EGFET and SnO2/ITO/glass gate EGFET, respectively. The characteristics of the EGFET have high performances such as a linear pH sensitivity of approximately 56 to 58 mV/pH in a concentration range between pH2 and pH10. Besides that, two clock signals were used to control the data of readout circuits and devices. Especially, the device of the array pH sensor has increased the resolution and decreased the noise. In addition, this invention has other advantages, such as the inexpensive fabrication system, low cost, and mass production characteristics. Based on the above characteristics, a disposal sensing device can be achieved. Thus, this invention has a high feasibility in array pH sensor.

Description

1223062 发明 Description of the invention: [Technical field to which the invention belongs] The present invention relates to an end reading circuit device of an array + iris early J-type acid-base ion sensing element, particularly a type of extended type Acid-detecting ion-sensing field-effect transistor to make an array of acid quot; "Method and device for osmium ion-sensing element and readout circuit" This architecture combines biosensing ^, 卞 心 衣 为 亚 and back end Readout circuits are matched to make a complete array of bio-sensing element systems. This invention can be used for medical detection, circuit design, semiconductor component manufacturing, etc. [Previous Technology] Traditional ion-selective glass electrodes have many advantages, such as: high linearity, good ion selectivity, and good stability. However, due to the shortcomings such as the large size and the long reaction time, it gradually turned to field-effect ion sensing elements developed with mature Shixi semiconductor integrated circuit process technology to replace traditional ion-selective glass electrodes [1J . In 1970, PietBergveld [2] first removed the general metal-oxygen half-field-effect crystal and the metal part of the gate. Then, the element is immersed in an aqueous solution, and the oxide layer on the gate of the element is used as an insulating ion sensing film. When it comes into contact with a solution with a different pH value, different potential changes will occur at the interface in contact with the solution, thereby making its channel The current is changed to measure the test value in water solution or the concentration of other ions, so Piet Bergveld calls it a field-effect ion sensing element. In the 1970s, the development and application of field-effect ion sensing elements were still at the exploratory stage [3]. However, by the 1980s, the field research of field-effect ion sensing elements had improved to another new level, and it had greatly improved a lot in terms of basic theoretical research, key technologies, and applied research. For example, based on the structure of the field-effect ion sensing element, the type of field-effect transistor for measuring various ions and chemical substances has been further advanced. There are more than two or thirty types of field-effect transistors. There has been considerable progress in the areas of modularization, modularization, and multifunctionality [3-6]. The main reason why the field-effect ion sensing element has become global in just ten years is that it has the following characteristics that traditional ion-selective electrodes do not have [3]: Solution measurement. 2. Two input impedances and low output impedance. Due to the above advantages of field-effect ion-sensing elements, more than two decades of research units have caused a wave of research on field-effect ion-sensing elements. At this time, the development of such elements The more important developments are as follows: (-) Field-effect ion-sensing elements with ion dioxide, nitride-titanium oxide, tantalum oxide, and oxide inscription as the ion-sensing film [7]. (II) Field-effect ion-sensing elements with different element structures: such as back-contact field-effect-type ion-sensing elements [8], amorphous osmium film transistor-based elements 6 1223062 sensing field-effect transistors, etc. [9]. (3) Miniaturization of the reference electrode [10]. (4) Differential field-effect ion sensing element [11]. (5) Enzyme is fixed to the field-effect ion sensing element to sense the body's heart in the living body (such as the glucose sensing or the oxygen content in the blood ... etc.) [12] ]. (6) Research on the theory of physics ... Adsorption bond model to learn. (7) Research on packaging materials, etc. [14]. (8) Integration of measurement system and sensing element [15]. (9) Research on simulation of field-effect ion sensing element [16]. Extended ion-sensing field-effect transistor. An element developed from self-sensing field-effect transistor. Its first pure Upiegd proposed [17], which is different from traditional ion-sensing field-effect transistor. The transistor retains the original metal gate in the metal-insulating layer-semiconductor transistor, and the sensing film is plated on the other end of the metal free-electrode extension. Extended ion-sensing field-effect transistor has the following advantages over traditional ion-sensing field-effect transistor, including: the electrostatic protection provided by the wire to the component; (2) the transistor of the component can avoid direct contact with the aqueous solution; ⑶ can reduce Effect of light on components [18].

Although the first EGFET appeared in 7 years in 983], there are not many papers published in international journals. After the year, no researchers have found any relevant papers published in international journals. It was not until this year 'that the research group published related papers on coffee T 7 1223062 [19]. Then the research group proposed an improved EGFET structure [20-21], which is divided into two parts: one is the sensing part of the Sn02 / Al / Si02M structure, and the other is the part of the readout circuit. The conventional technology has been patented as follows: (1) Barry W. Benton, USP 5,833,824; Date of patent: Nov 10, 1998 "Dorsal substrate guarded ISFET sensor", this patent shows that the ion sensing element is used for The ions in the solution are detected, which include a substrate portion and an ion field effect sensing transistor portion. The front part of the substrate is immersed in water, and the front and back ends of the substrate are connected in a void manner. This patent is to connect the back of the substrate to the front-end sensing element in a void manner to achieve the purpose of sensing. Only the back is immersed in the measurement during measurement. In solution. % (2) Graham Anthony Fuggle, U $ P 6,353,323; Date of patent: Mar 5, 2002 "Ion concentration and pH measurement", this patent illustrates an instrument method and measurement method for processing the front-end sensing elements, and the front-end Ion sensing: The component device contains a total of ion-selective electrodes. A reference electrode and an ion-sensing field effect transistor must be immersed in the solution to be tested, the sensing element is connected to the front-end circuit, and the reference electrode is connected to the back-end circuit, thereby separating the component from the reference electrode to Achieve common use of a single reference electrode for multiple sensing elements. (3) Nicole Jaffrezic-Renault, Jean-Marc Chovelon, Hubert Perrot, Pierre Le Perchec, Yves Chevalier, USP 5,350,701; Date of patent: Sep 27, 1999

Process for producing a surface gate of an integrated electro-chemical sensor, 8 1223062 consisting of a field-effect transistor sensitive to alkaline-earth species and sensor obtained ", this patent describes a production improvement method, that is, the surface of the gate is treated, The gate surface includes an ion-selective film as a complete chemical sensing element. A chemically synthesized phosphide-based sensing film is deposited on the gate region of the field-effect ion sensing element. Alkaline earth metals will have a reaction change. Using this element to detect the content of alkaline earth metals can be used as a detector for the content of earth metals, especially for the detection of # 5 ion content. (4) Byung K. Sohn , Dae H · Kwon, USP 5,319,226; Date of patent: Jun 7, 1994 a Method of fabricating an ion sensitive field effect transistor with a Ta205 hydrogen ion sensing membrane ", this patent illustrates the use of radio frequency Deposited on a non-conducting silicon nitride film, that is, on the gate region of an ion sensing element, Button forming an oxide / silicon nitride / type field effect ion sensing element structure of silicon dioxide. The thickness of the oxide button film is 40 10-9 to 5Q 10-9 meters, and then annealed in an oxygen environment at a high temperature of 375 to 450 degrees for one hour. 0 (V) Alastair Sibbald, USP 4,657,658; 1987 "Semiconductor devices", this patent describes the use of a complete semiconductor circuit as a physical or chemical sensing element. Its instrumentation includes a pair of semiconductor elements of similar architecture and structure, and its readout circuits are connected to the same circuit. The whole structure is a metal-oxygen half-field effect transistor and a field-effect ion sensing element, forming a differential pair system module system. 9

(6) Masahiro Shima, USP 5 Q9, m · r ”-I, 183, Date of Patent: Jul 13, 199 < Metal oxide matrix biosenςπΓς ",, ^ sensors using metal oxide films as substrates for biomolecules' This architecture is suitable for the development of electrochemical biosensors. The most common metal oxide film is a water-containing metal oxide, which may be a conductor or a semiconductor, and has good stability in water-soluble or non-water-soluble solutions. Will not be dissolved by the solution or carry out irreversible reactions. This metal oxide can be used to make current-type or potential-type bio-sensors at the same time.

Sensing is performed on antibodies, antibodies, antigens, DNA sequences, and the like. The iridium oxide film is the most representative metal oxide film, with the best sensing characteristics. In addition, metal oxides such as nails, titanium palladium and 4 white Cu also have similar characteristics. The use of metal oxides can avoid oxidation. Dangerous, according to the current literature report [22], located on the gate oxide layer field-effect ion-sensing electro-solar body, the most commonly used hydrogen ion sensing film is ... Xi, minus group and oxidation! g and other materials; field-effect ion-sensing tritium oxide crystals using trioxide as the hydrogen ion sensing film were produced for the first time in this laboratory. It has a near Nernst response at 56 ~ 58mV / pH || _ 'High drift and long-term stability, low drift characteristics, response rate of less than 0.1 second, and under appropriate operating current, the temperature coefficient of the component can be reduced to zero, etc. 0 Ion-sensing field-effect transistor can be used Relevant semiconductor processes are fabricated into array-type ion sensing elements, so the number of detection samples of the sensing elements can be increased. 10 Multi-point 单 j single-test object f method is used to reduce the detection error of single-sensor elements' Therefore, when it is used for the detection of radon ion concentration in the human body, the detection accuracy of the sensor it will improve the detection accuracy, reduce the measurement error of the sensing element, and improve the medical nuclear testing characteristics; and the ion sensing field effect transistor can be miniaturized Due to its characteristics, when it is made into an array type sensing element, the amount of human body fluid can be reduced to achieve the purpose of trace detection. Because the ion-sensing field effect transistor has the characteristics of fast response, it is made into When the array material senses S pieces, it can also have the characteristics of real-time monitoring of the solution under test, which can reduce the measurement time of the object under test. It can be seen that the above-mentioned technologies still have many shortcomings. They are not a good designer and need to be improved. In view of the various deficiencies derived from the above-mentioned conventional technology wheel, the inventor of this case has been eager to improve and innovate. After years of painstaking research, he has finally successfully completed the production and back end of the array type acid-base ion sensing element. Readout circuit device. [Summary of the Invention] The purpose of the present invention is to provide an array type acid-base ion sensing element manufacturing and back-end readout circuit device. With this manufacturing method, the manufacturing method has simple manufacturing system, low cost, and can be manufactured in large quantities. The advantage is that it can also produce a low-cost and disposable throwing type sensing element. Therefore, the present invention has extremely high feasibility and applicability in the array type acid-base ion sensing element. Fabrication of an array type acid-base ion sensing element capable of achieving the above-mentioned object of the invention and a rear-end circuit circuit are proposed. An extended acid-base ion sensing field effect transistor is proposed as an array type acid-base ion sensing. Force method and device of element and related readout circuit; therefore, what the present invention emphasizes is that by using this method and device, an array type sensing element structure can be fabricated: sensing film / metal / silicon dioxide multilayer structure Multilayer structure sensing element for sensing element and sensing film / indium tin oxide / glass substrate and back-end readout circuit. [Embodiment] The fabrication of an array type acid detection ion sensing element and back-end readout circuit device provided by the Institute & this is to deposit a semiconductor acid detection sensor film on a non-insulating substrate to produce a separate type Array-type sensing element, and use this element to measure the acid value of the solution; and use the semiconductor standard process to make the circuit of the array-type sensing element 'This readout circuit contains the acid-sensing element before reading Out circuit 'multiplexer, back-end buffer circuit, amplifier circuit. This array-type sensing element can be integrated into an acid-testing array-type sensing element with a hybrid architecture. Compared with the single-sensing element, the advantages of this array structure are that it can hold a large number of signals. It reduces the error of the single-signal and improves the accuracy of the sensing element. The higher the stability, the more accurate. " The manufacturing process of the array-type sensing element is as follows: the thickness of the silicon dioxide layer is 1000 1 · P type Shixi substrate 'resistance = 4 ~ 7 ohm-cm; 1223062 1223062 3. using a metal mask to sputter 4 · Recycling with epoxy resin into 2 · Using metal mask to grow aluminum film with vacuum frosting machine; growing finished product of tin dioxide film. It is produced by using the relevant process conditions of UMC as shown in the 0.5 micron (// m) figure ΐ. The readout circuit device part is manufactured by 2P2M n-well process technology. The characteristics of each layer are as follows: 1. Cpoly thickness 〇2 micron; 2. GPoly thickness 〇3 micron; 3. Metall thickness 0.6 micron "Metal2 thickness u micron howl; 5. PaSSivati〇n thickness 0.7 micron (factory called 6. interpolar oxidation The thickness of the layer is 135 angstroms. 7. The total area u used by the wafer is squared (_2). Please refer to Figure-, which is a cross-sectional view of the Sn〇2 Qu〇2 / Si sensing architecture. Easy and can be manufactured with cm0s standard process. Its structure can be tin dioxide, a genus of _dioxy cut structure, which is based on the substrate I] = deposition layer 12 and dioxide _13, and epoxy resin is used on the outer layer. ㈣The coating is covered to form a “slot” and the wire 4 is led out by the aluminum layer 12. Refer to FIG. 2 for a cross-sectional view of the Sn〇2 / jT〇 / glass sensing architecture. It can be seen from the figure that the glass substrate The price is cheap, so the sensing element obtained by the manufacturing method of this structure is suitable for disposable applications. Its structure is two Tin oxide-indium tin oxide 13 glass substrate structure 2, tied to a broken glass substrate 1, indium tin oxide layer 22 and two emulsified tin layers 23 are deposited, and the epoxy resin is packaged with a 4-port knife to form a The slot is read, and the V line 4 is read out by the indium tin oxide layer 22. 凊 Refer to Figure 3 'for the manufacturing process of the array type acid detection ion sensing element. It can be seen from the figure that the material has acid detection ion sensing. The manufacturing process of the measuring device is as follows: 1. Prepare a silicon substrate 31, which can be a p-type Shixi substrate, and its resistance value is 4 ~ 7 ohm-cm '. It can also be made with broken glass substrate, ceramic substrate or high-blade on 4 substrates, which will make the produced components have a wider range of applications; 2. Use metal masks to grow aluminum thin film magic with a vacuum evaporation machine; 3 · Using a metal mask to grow a tin dioxide film by a sputtering machine 33 4. Reuse epoxy resin vinegar 34 to seal the finished product. Using this method, several pieces are easy to produce, that is, the production process does not need to be coated with a photoresist liquid and a resist. The relevant thin film is etched, etc. Read more Figure 4 'is a schematic diagram of the | g layer mask, as can be seen from the figure, this is a ^ It is made! Lu Guang mask, the part of the film to be deposited is the black knife in the figure. It is to remove the metal mask, and then when depositing the thin film, it will only be deposited on the metal part of the mask that has been removed. Refer to Figure 5 for a schematic diagram of the tin dioxide mask of the sensing film. From the figure, this is a tin dioxide mask made of a metal. The thin portion of tin dioxide 14 1223062 to be deposited is shown in the figure. The black part is etched away from the metal photomask, and when the tin dioxide film is deposited, it will only be deposited on the metal part of the photomask that has been removed. The sound is Γ26, which is the whole of the array-type sensor element. Architecture :: Picture, as can be seen from the figure, the front end has four sensing elements and is equipped with four front ^ circuits to read the signals of individual components, and the back-end circuit is used to route the front lightning to the moon " and the circuit and control The circuit is wide ... The array-type back-feed circuit can be = 2 signals' and amplified and interpreted separately, so if the multiplexer is modified, n various array-type sensing element circuits can be made. Therefore, the array-type sensing Element circuit, can be widely used in potentiometric sensing The element; production. Please refer to Figure 7 for the front-end readout. The circuit architecture diagram is composed of four CMOS M chips, so as to reduce the layout area.糸 Please refer to Figure 8 for the schematic diagram of the round-to-output ratio of the front-end readout circuit. It can be seen from Tanaka that the output voltage will be shifted by the circuit to the round-to-output ratio of 0J18, that is, the signal will be reduced by the circuit. It is known that the structure of the switch circuit of the control part is shown in Figure 9. It can be composed of an inverter circuit (hlverter) and a CMOS switch circuit. Please refer to Figure 10, which is the second part of the control part. Four decoder circuit architecture diagram, as can be seen from the figure, is composed of six inverter circuits (inverter) and four two worm wheel into 15

Nand circuit. Please refer to Figure 11 for a schematic diagram of the voltage output wheel-in ratio of the combination of the front-end circuit and the control circuit. From the figure, it can be seen that the output voltage will be shifted to 5 V by the circuit, and the input-output ratio is 0.675, that is, the signal will be further reduced by the control circuit. Refer to Figure 12 for the circuit output of the array type acid-base ion sensing element

Schematic diagram of out-to-round ratio. As can be seen from the figure, it is the measurement result of the array-type sensing element circuit. The amplification of the back-end circuit can restore the sensing film signal to its initial value, and its final input voltage and output voltage. The ratio is 丨 .04. Please refer to FIG. 13 for a schematic diagram of the readout signal of the array type acid-base ion sensing element. As can be seen from the figure, the observable dagger indicates that the element is well-made, and the signal is stable, and please refer to FIG. 14 The calibration curve diagram measures linearity as high as good.

'It is the read-out signal of the array type acid ion sensing core, which can be known from the figure.' The calibration curve can obtain the element sense. 〇 Zheng shows the characteristics of this array type ion sensing element. Please refer to Figure 15 for the phase of the wafer. , Bi-polycrystalline silicon bimetal, 05 diagram, showing the front-to-back relationship between the layers. The above detailed description is a cross-sectional view of the structure of the present invention. The structure of the micron and n-type wells from the structural section in the figure, but this embodiment is not intended to limit the date of issue.专利 The patent scope of the specific description of the embodiment, where it does not depart from 16 1223062 Figure 13 is a reading diagram of the array type acid-base ion sensing element, and Figure 14 is a schematic diagram of the reading curve of the array type acid-base ion sensing element; And FIG. 15 is a cross-sectional view of a related process structure of a wafer. [Representative symbols of main parts] 1 Tin dioxide-aluminum metal-two gasification seconds structure 11 substrate 12 aluminum layer 13 tin dioxide layer 14 epoxy resin $ 2 tin dioxide-indium tin oxide t slope substrate structure 21 glass Substrate 22 Indium tin oxide layer 23 Tin dioxide layer 24 Epoxy resin 31 Silicon substrate 32 Aluminum thin film 33—Tin oxide thin film 34 Epoxy resin 4 Wire output signals indicate signal correction 1223062 [References] [1] P. Bergveld and A. Sibbald, “Analytical and biomedical application of ion-sensitive field effect transistor”? Elsevier Secience Publishing Company Inc., New York, ρρ · 2-60, 1988.

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Claims (1)

Scope of patent application: 1. _ Fabrication of an array type acid-base ion sensing element and back-end readout circuit device 'deposition a semiconductor acid-base sensing film on a non-insulating substrate to produce a separate array type Sensing element, and use this element to detect the parametric test value of the solution, and use the semiconductor standard process to make the output circuit of the array sensing element; combining this array sensing element with the back-end readout circuit device Fabricated into an acid-base array sensing element with a hybrid architecture. 2 Fabrication of an array type acid-base ion sensing element and a back-end readout circuit device as described in item 1 of the scope of patent application, wherein the manufacturing steps of the array type sensing element are: Step 1: Prepare a substrate; Two: Use a metal mask to grow an aluminum film with a vacuum evaporation machine; Step two: Use a metal mask to grow a tin dioxide film with a sputtering machine; Step four: Use epoxy resin to encapsulate the finished product. 3_ Fabrication of an array type acid-base ion sensing element and back-end readout circuit device as described in item 1 of the scope of patent application 5 wherein the structure of the array sensing element may be tin dioxide / metal / two Silicon oxide multilayer structure sensing element or tin dioxide / indium tin oxide / glass substrate multilayer structure sensing element. 4. The production of the array type acid-base ion sensing element and the back-end readout circuit device according to item 1 of the scope of patent application, wherein the readout circuit includes: a readout circuit before the sensing element, a multiplexer , Back-end buffer circuit and amplifier