KR200408169Y1 - One chip gas sensor for detecting multi gases fabricated bridge on micro channel - Google Patents

Abstract

The present invention relates to a single-chip gas sensor for gas detection having a bridge structure that can simultaneously detect multiple gases on a single chip.

The present invention has a directional silicon substrate, an insulating layer formed on the silicon substrate, a microchannel formed by etching the silicon substrate to a predetermined depth, microelectrode lines formed in pairs on the microchannel, A micro heater line electrically separated from the micro electrode line on the micro channel to surround the micro electrode line, a plurality of electrode pads for connecting the micro electrode line and the micro heater line to an external circuit, and one of the micro electrode lines It comprises a pair and a sensing film covering a part of the fine heater wire, the structure is characterized in that it is possible to detect one or more multi-gas by arranging one or more microelectrode wires, micro heater wires and electrode pads, the structure is simple yet consumed The power can be minimized, and the structure can be arranged to detect multiple gases. The present invention provides a single-chip gas sensor for detecting a gas having a bridge structure.

Micro channel, micro heater line, micro electrode line, single chip gas sensor

Description

One chip gas sensor for detecting multi gases fabricated bridge on micro channel}

1 is a plan view showing a structure before a sensing film of a single-chip gas sensor is formed according to an embodiment of the present invention;

2 is a perspective view of FIG.

3 is a perspective view illustrating a structure after a sensing film is formed in the single chip gas sensor illustrated in FIG. 1;

4 is a view sequentially showing a manufacturing method of a single-chip gas sensor according to an embodiment of the present invention;

5 is a plan view showing a single chip gas sensor according to another embodiment of the present invention;

6 is a plan view showing a single chip gas sensor according to another embodiment of the present invention;

7 is a plan view showing a single chip gas sensor according to another embodiment of the present invention;

8 is a plan view illustrating a single chip gas sensor according to another exemplary embodiment of the present invention.

＊ Explanation of symbols on major part of drawing ＊

101: silicon substrate 102: insulating layer

103a / b: fine heater line 104a / b: fine electrode line

105a / b, 106a / b: electrode pad 107: micro channel

201a / b: sensing film 301: photosensitive agent

302: metal layer

The present invention relates to a sensor for gas detection, and more particularly, a single gas detection sensor having a bridge structure that enables simple sensing and minimizing power consumption, as well as simultaneously detecting multiple gases on a single chip. It relates to a chip gas sensor.

Gas sensors, which have been continuously developed due to the demand for toxic and explosive gas detection, have been actively trying to use the gas sensors for measuring the atmospheric environment due to environmental problems.

Air pollution is very serious because it not only affects human health and hygiene, but also extends to the global scope. Therefore, continuous monitoring and control of harmful substances is urgently needed.

In addition, as the society is gradually urbanized and industrialized, the demand for gas is soaring, and as a result, the loss of fire and human damage due to gas leakage is rapidly increasing. There is a need for a gas sensor to detect multiple gases applicable.

In general, the gas sensor is a kind of chemical sensor and is one of the high-performance artificial sensory organs that compensates for the incompleteness of the sense of smell and expands its function.

Among the myriad of sensors on earth or developed by humans, gas sensors are the basis for targeting the air, an essential element for sustaining all life.

To date, the continued development of gas sensors has enabled the acquisition of higher performance devices and systems at lower cost.

Therefore, the present invention is to provide a semiconductor gas sensor to be applied to the continuous monitoring and control of harmful substances and food, perfume industry and medical field using a variety of raw materials.

Semi-conductor type gas sensor, which is being researched, can be classified into thick film type and thin film type according to the application form of sensing material, and it is gradually being miniaturized into bulk type / thick film type / thin film type / micro type.

Recently, research on a sensor array combining several of these sensors has been conducted.

However, in the case of the conventional micro gas sensor, there is a problem in that a structure for detecting individual gases or a sensor for detecting multiple gases has a complicated structure including a plurality of heaters and a plurality of sensing units.

The present invention was devised to solve the above-mentioned problems of the prior art, and the present invention constitutes a micro heater line and a fine electrode line having a bridge structure on a microchannel fabricated by using semiconductor micromachining technology, and the structure is simple. It is an object of the present invention to provide a single-chip gas sensor for gas detection that has a bridge structure that can minimize power consumption and can arrange multiple structures to detect multiple gases.

Gas detection single chip gas sensor having a bridge structure according to the present invention for achieving the above object,

A directional silicon substrate, an insulating layer formed on the silicon substrate, a microchannel formed by etching the silicon substrate to a predetermined depth, microelectrode lines formed in pairs on the microchannel, and on the microchannel A micro heater line electrically separated from the micro electrode line and surrounding the micro electrode line, a plurality of electrode pads for connecting the micro electrode line and the micro heater line to an external circuit, a pair of the micro electrode line, and the And a sensing film covering a portion of the fine heater line.

Here, it is preferable to arrange one or more micro heater lines surrounding the micro electrode lines and the pair of micro electrode lines to detect multiple gases.

 The insulating layer formed on the silicon substrate is at least one of a silicon oxide film (SiO 2), a silicon nitride film (Si 3 N 4), an oxide film-nitride film-oxide film (SiO 2 -Si 3 N 4 -SiO 2), a silicon carbide film (SiC), or a diamond thin film. It is preferable that the above film is formed.

In addition, the structure of the micro channel is preferably made of a polygonal structure.

In addition, the pattern of the pair of microelectrode lines is made of a II-shaped structure, the pattern of the fine heater line is a curved structure is preferably made of a structure such that the microelectrode line is formed therein to be surrounded by the fine heater line.

In addition, the pattern of the pair of microelectrode lines has a II-shaped structure, and the pattern of the micro heater line has a multi-curve structure, and a pair of microelectrode lines are formed in each bend so that a plurality of microelectrode lines surround one microheater line. It is preferable that the structure is made to be wrapped.

In addition, in constructing a gas sensor to detect two or more micro-electrode lines and micro-heater lines to detect multiple gases, the pattern of the pair of micro-electrode lines has an II structure, the pattern of the fine heater line It has a structure in which a microelectrode line is formed in the curved structure so as to be surrounded by the micro heater line, and the micro electrode line and the micro heater line constituted in this way form a micro electrode line in the center and are arranged on both sides. It is preferable to configure the pattern so that the micro heater lines surrounding the micro electrode lines are commonly used.

Hereinafter, with reference to the preferred embodiment shown in the accompanying drawings of the present invention will be described in detail the configuration and operation thereof.

1 is a plan view illustrating a structure before a sensing film of a single-chip gas sensor having a micro heater structure and a plurality of micro electrode lines according to an embodiment of the present invention is formed, and FIG. 2 is a perspective view of FIG. 3 is a perspective view showing the structure after the sensing film is formed in the single-chip gas sensor shown in FIG.

1, 2 and 3, the single-chip gas sensor according to the present invention, a silicon substrate 101 having a direction, an insulating layer 102 formed on the silicon substrate, and the silicon substrate ( A microchannel 107 formed by etching 101 to a predetermined depth, microelectrode lines 104a and 104b formed in pairs on the microchannel 107, and the microelectrode lines 104a and 104b on the microchannel. A microheater line 103a, 103b, and the microelectrode line 104a, 104b and the microheater line 103a, 103b which are electrically separated from each other and surround the microelectrode lines 104a and 104b, respectively. A plurality of electrode pads 105a, 105b, 106a and 106b for connection to the plurality of electrode pads, a pair of the microelectrode lines 104a and 104b, and a sensing film 201a and 201b covering a part of the microheater lines 103a and 103b. It is configured to include).

According to an embodiment of the present invention having such a configuration, the fine electrode line 104b, the fine electrode line 103b, the fine heater line 103b, the electrode pad 105b, and the fine electrode line 104a, the fine 103a, and the electrode pads 105a and 106a are arranged in space. 106b) shows a single-chip gas sensor for multi-gas detection for detecting two gases.

In the gas sensor of the present invention, the micro heater wires 103a and 103b, the microelectrode lines 104a and 104b, and the lower surfaces of the electrode pads 105a, 105b, 106a and 106b leak through the silicon substrate 101. An insulating layer 102 is formed to insulate between the current and the electrode pads 105a, 105b, 106a, 106b.

The insulating layer 102 is formed of at least one of a silicon oxide film (SiO 2), a silicon nitride film (Si 3 N 4), an oxide film-nitride film-oxide film (SiO 2 -Si 3 N 4 -SiO 2), a silicon carbide film (SiC), or a diamond thin film. Can lose.

The insulating layer 102 is grown to a predetermined thickness by using chemical vapor deposition or an electric furnace, and partially wet-etched to form the microchannel 107.

The microelectrode lines 104a and 104b are formed in two pairs on the microchannel 107, and have a "II" structure in which two pairs are formed in one pair.

The fine heater lines 103a and 103b are formed to be electrically separated from the microelectrode lines 104a and 104b on the microchannel 107. The micro heater lines 103a and 103b surround the microelectrode lines 104a and 104b and are connected to one or two as a whole. Is formed.

The fine heater lines 103a and 103b have a refractive pattern.

The electrode pads 105a and 106a, the fine heater line 103a, and the fine electrode line 104a have a low oxidation reaction and high electrical conductivity, such as nickel (Ni), palladium (Pd), platinum (Pt), and gold (Au). It is made by depositing with the same metal material.

The fine heater lines 103a and 103b and the II-pattern fine electrode lines 104a and 104b on the microchannel 107 are fine heater lines 103a and 103b and microelectrode lines 104a and 104b. A plurality of sensing films 201a and 201b covering the gaps are formed.

Each of the formed sensing films 201a and 201b is designed to detect multiple gases (two types).

The micro channel 107 is a structure for minimizing heat dissipation of the fine heater lines 103a and 103b to minimize power consumption, and the formation of the micro channel 107 uses wet etching.

3 illustrates a plurality of sensing layers 201a and 201b formed by screen printing each sensing material on the plurality of microelectrode lines 104a and 104b in the structure of FIG. 1.

Here, the reaction of the specific gas and the plurality of sensing films 201a and 201b will be described below.

When power is applied to the fine heater wires 103a and 103b, heat is generated by resistance according to the thickness and length of the metal layer forming the fine heater wires. This heat generation causes the temperature of the fine heater wires 103a and 103b to reach a specific temperature. Is raised.

Here, the temperature of the sensing films 201a and 201b formed on the plurality of microelectrode lines 104a and 104b is also raised to facilitate the chemical adsorption or desorption reaction to the gas introduced therein.

As a result, resistance changes occur in several sensing layers 201a and 201b, and the resistance change is measured in each of the microelectrode lines 104a and 104b.

4 (a) to (f) sequentially illustrate the manufacturing process of the gas sensor according to an embodiment of the present invention.

The insulating layer 102 of 1 μm or more is grown to insulate the leakage current and to insulate the electrode pads 105a and 106a. First, as shown in FIG. 101, an oxide film (SiO2), a silicon nitride film (Si3N4), an oxide-nitride film-oxide film (SiO2-Si3N4-SiO2), a silicon carbide film (SiC), or a diamond thin film is deposited on a chemical vapor deposition or electric furnace. The insulating layer 102 is formed by growing at least 1 μm using a furnace.

As shown in FIG. 4B, the photoresist 301 is patterned on the insulating layer 102 to form the microchannel 107 and the automatic cutout 303.

The automatic cutting unit 303 is formed to cut each sensor unit after the process is completed, is formed using a cutting device after the process is completed, in the present invention to be formed together when forming the micro channel 107 The photosensitive agent 301 is applied to further include the process of forming the automatic cutting unit 303.

That is, the photosensitive agent 301 is applied to the portion where the upper end pattern is formed, and after the drying, the photosensitive agent 301 is applied to the lower end where the automatic cutting part 303 is to be formed.

As shown in FIG. 4C, the insulating layer 102 is patterned using wet etching.

As shown in (d) of FIG. 4, the fine heater line 103a, the fine electrode line 104a, and the electrode using a vacuum evaporation method, an e-beam evaporation method, or a sputter system. The metal layer 302 is deposited on the pattern portions of the pads 105a and 106a using titanium (Ti), chromium (Cr), gold (Au), or the like to form the fine heater line 103a, the fine electrode line 104a, and the electrode. The pads 105a and 105b are formed.

The metal layer 302 is used as a seed layer, and a deposition thickness of titanium (Ti) or chromium (Cr) is 500 Å and gold (Au) is deposited at a thickness of 500-800 Å.

The width of the pattern of the fine heater line 103a and the fine electrode line 104a is 10-20 μm, and the distance between the fine heater line 103a and the fine electrode line 104a is also designed to be 10 μm.

In this case, in general, when the fine electrode line 104a, the fine heater line 103a, and the electrode pads 105a and 106a are configured using only platinum (Pt), gold (Au), manufacturing cost may be a problem. The method may further include plating nickel (Ni).

The reason for plating nickel is to use it as a heater. In general, as the heater material, as described above, precious metal platinum or gold is used. In the present invention, the effect of cost reduction of the product and the performance of platinum are almost the same. One nickel may be used.

In order to plate nickel, a conductive material is required to deposit gold, and gold has a poor adhesion with a silicon material, and thus nickel or chromium or titanium is deposited before the gold is deposited.

Therefore, nichrome or chromium or titanium is first deposited, gold is deposited thereon, and the final nickel is plated.

As shown in FIG. 4E, the wet etching is performed using potassium hydroxide (KOH) to form the microchannel 107 having a depth of 140-150 μm and the automatic cutout 303.

Therefore, the initial thickness of the silicon substrate of 500㎛ has a thickness of 200-220㎛ due to the etching of the upper and lower surfaces.

As shown in FIG. 4F, the sensing film 201a is coated to cover a part of the fine heater line 103a and the fine electrode line 104a to complete the manufacturing process.

5, 6, 7, and 8 illustrate a preferred embodiment according to the pattern deformation of the micro heater line and the plurality of micro electrode lines, which are main parts of the single-chip gas sensor for detecting multiple gases of the present invention.

In the embodiment shown in FIG. 5, micro heater lines 403a and 403b having a "c" pattern and microelectrode lines 404a and 404b having two pairs of II-shaped patterns are formed on the microchannel 107. It shows an example designed to detect the gas.

In the embodiment shown in FIG. 6, the micro heater lines 503a and 503b of the "c" pattern and three microelectrode lines 504a, 504b and 504c of the II-shaped pattern are formed on the microchannel 107 at the same time. This example is designed to detect gas in branches.

In the case shown in FIG. 6, one side of the fine heater lines 503a and 504b is commonly used in the fine electrode lines 504C to form a pattern for sensing three gases appropriately in the space.

In the embodiment shown in Fig. 7, two microelectrode lines 604a and 604b of II-shaped pattern are formed in the micro heater 603 of the " l " pattern on the microchannel 107, respectively. It is designed to detect.

The embodiment shown in FIG. 8 is a variation of the embodiment shown in FIG. 7, and the micro heater 703 having a "d" pattern on the micro channel 107 and two fine electrode lines 704a having an II pattern. 704b) is designed to detect two gases at the same time.

According to the present invention as described above, the single-chip gas sensor according to the present invention is produced by forming a micro heater line and a plurality of micro electrode lines on the micro channel.

There is a micro heater line required to heat the sensing material on the microchannel, and a sensing film related to the number of microelectrode lines is coated on the plurality of microelectrode lines so as to detect multiple gases at the same time.

In order to obtain a high temperature of 200 ° C. or higher required for gas detection, a structure in which a micro heater line is enclosed is used so that the sensor has the same temperature around a plurality of micro electrode lines.

The electrode pad was formed by depositing a metal layer on the insulating layer formed on the silicon substrate to prevent electrical malfunction such as insulation and blocking leakage current from the silicon substrate, and vacuum deposition, electron beam vacuum deposition, sputtering method on the micro heater line and the plurality of micro electrode lines. Alternatively, a sensing material may be formed by a screen printing method to detect various gases at the same time.

According to the pattern change of the micro heater line and the micro electrode line, it is possible to construct a gas sensor that can detect one or more multiple gases through appropriate space utilization in a single chip, and the difference in temperature of the micro heater line may occur according to the pattern change. It can affect the reliability of the operation.

In the present invention has been described with reference to the preferred embodiment as described above, it can be carried out by modifying a variety of patterns.

As described above, according to the gas detection single-chip gas sensor having a bridge structure according to the present invention, the optimum response to the multiple gas generated simultaneously due to the rapid response speed, low power consumption and industrial advancement At the same time, it is possible to detect mass production by simplifying the size and process of the single-chip gas sensor.

Therefore, it can detect explosive gas and toxic gas at an early stage and respond to accidents, and can remove the inconveniences of life through environmental control of humidity, alcohol and odorous gas in the industrial, environmental and medical fields. Easy to apply

Claims (7)

A silicon substrate having directivity; An insulating layer formed on the silicon substrate; A micro channel formed by etching the silicon substrate to a predetermined depth; Microelectrode lines formed in pairs on the microchannels; A fine heater line electrically separated from the microelectrode line on the micro channel to surround the microelectrode line; A plurality of electrode pads for connecting the micro electrode lines and the micro heater lines to an external circuit, respectively; And a sensing film covering a pair of the microelectrode lines and a portion of the microheater line. The method of claim 1, The gas detection single chip gas sensor having a bridge structure, characterized in that for detecting multiple gases by arranging one or more micro heater lines surrounding the micro electrode line and a pair of micro electrode lines. The method of claim 1, The insulating layer formed on the silicon substrate may be at least one of a silicon oxide film (SiO 2), a silicon nitride film (Si 3 N 4), an oxide film-nitride film-oxide film (SiO 2 -Si 3 N 4 -SiO 2), a silicon carbide film (SiC), or a diamond thin film. Gas detection single chip gas sensor having a bridge structure, characterized in that consisting of a film. The method of claim 1, The micro-channel structure of the gas detection single-chip gas sensor having a bridge structure, characterized in that consisting of a polygonal structure. The method according to any one of claims 1 to 4, The pair of microelectrode lines have a II-shaped structure, and the pattern of the micro heater lines has a bridge structure, characterized in that the structure of the microelectrode lines is formed in the structure to allow the microelectrode lines to be surrounded therein and surrounded by the micro heater lines. Single chip gas sensor for detecting gas. The method according to any one of claims 2 to 4, The pair of microelectrode lines has a II-shaped structure, and the pattern of the micro heater lines has a multi-bending structure, and a pair of microelectrode lines is formed in each bend so that a plurality of microelectrode lines may be surrounded in one microheater line. Gas detection single chip gas sensor having a bridge structure, characterized in that consisting of a structure. The method according to any one of claims 2 to 4, In constructing a gas sensor that detects multiple gases by arranging two or more microelectrode lines and micro heater lines, The pattern of the pair of microelectrode lines is made of a II-shaped structure, the pattern of the fine heater line is a curved structure is made of a structure such that the microelectrode lines are formed therein to be surrounded by the fine heater line, it is made of a structure A single-chip gas for gas detection having a bridge structure, comprising a microelectrode line formed at the center where the microelectrode lines and the micro heater lines are arranged, and a pattern configured to commonly use the microheater lines surrounding the microelectrode lines arranged at both sides. sensor.

Images