KR100937593B1 - Semiconductor gas sensor device and method for fabricating the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor gas sensor element and a method of manufacturing the same, wherein the single crystal silicon of a SOI silicon substrate is doped with impurities and used as a heater of the gas sensor, and the single crystal silicon is used as a sensor membrane. According to the present invention, the doped single crystal silicon is utilized as a heater and a sensor membrane, thereby improving the durability against heat stress when operating at a high temperature of 300 ° C. or higher. The effect is to minimize the loss to bulk.

Semiconductor Gas Sensors, Microelectromechanical Systems (MEMS), Silicon Micro Heaters

Description

Semiconductor gas sensor device and its manufacturing method {SEMICONDUCTOR GAS SENSOR DEVICE AND METHOD FOR FABRICATING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor gas sensor devices, and more particularly, to a semiconductor gas sensor device using a microelectromechanical integrated system (MEMS) technology and a method of manufacturing the same.

The present invention is derived from the research conducted as part of the IT source technology development project of the Ministry of Information and Communication and the Ministry of Information and Communication Research and Development. [Task Management No .: 2006-S-007-02, Task Name: Ubiquitous Health Management Module System]

Recently, Micro Electro Mechanical System-type gas sensor technology is in the spotlight due to the shift in our important perception of the environment. For gas sensors, sensitivity, stability, and selectivity are key parameters in evaluating gas sensor performance. In particular, in the heating type gas sensor, a method of manufacturing and heating a metal heater such as platinum on the upper and lower portions or in the middle of an existing oxide film or an insulating film has been frequently used in view of stability.

In general, when operating a MEMS type gas sensor, the sensor is operated at a high temperature of 300 ° C or higher. Here, the problem of the MEMS type gas sensor is that the durability against heat is significantly reduced when the heating is applied for a long time, which results in the sensor eventually being destroyed, which is a major obstacle in actual commercialization. Conventional MEMS type gas sensor method using platinum or tungsten as a heater material on oxide or insulator membrane has almost the problem of heat resistance in high temperature operation, which is a big obstacle to commercialization. have.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and an object of the present invention is to provide a semiconductor gas sensor device having improved thermal durability of a sensor membrane and a method of manufacturing the same.

Another object of the present invention is to provide a semiconductor gas sensor device and a method of manufacturing the same that can minimize the heat loss of the heater.

The semiconductor gas sensor device and the method of manufacturing the same according to the present invention for achieving the above object is characterized in that the thermal durability of the gas sensor device can be improved by using a single crystal silicon used as an electrode as a heater. In addition, the semiconductor gas sensor device and its manufacturing method according to the present invention is characterized by minimizing the loss of the heat of the heater by adopting the SOI substrate.

A semiconductor gas sensor device according to an embodiment of the present invention capable of implementing the above characteristics may include an oxide film disposed between an upper silicon film and a lower silicon bulk, and a portion of the lower silicon bulk is removed to expose a portion of the upper silicon film. A substrate comprising a cavity to make; A silicon heater composed of the upper silicon film; And a gas sensor disposed above the silicon heater.

In the semiconductor gas sensor device of the present exemplary embodiment, the upper silicon film may include a conductive single crystal silicon film doped with impurities.

In the semiconductor gas sensor device of the present embodiment, the cavity may be formed under the silicon heater to thermally isolate the silicon heater from the lower silicon bulk.

In the semiconductor gas sensor device of the present embodiment, the gas sensor includes: a sensor electrode disposed on the silicon heater with an insulating film interposed therebetween; And a sensing film made of a sensor sensitive material covering the sensor electrode.

In the semiconductor gas sensor device of the present embodiment, the gas sensor may further include a sensor seed film disposed between the sensor electrode and the sensing film to improve sensing sensitivity. The sensor seed layer may include nickel (Ni).

According to another aspect of the present invention, there is provided a semiconductor gas sensor device comprising: a substrate having an oxide film between a silicon film and a silicon bulk; A sensing region occupying a portion of the substrate and including a gas sensor utilizing a portion of the silicon film as a sensor membrane, and a heater constituting the sensor membrane and providing heat to the gas sensor; It occupies another portion of the substrate, characterized in that it comprises a peripheral region that is separated from the sensor region by a groove formed by removing a portion of the silicon film.

In another embodiment of the semiconductor gas sensor device, the sensing region may be electrically isolated from the peripheral region by the groove and surrounded by the peripheral region.

In the semiconductor gas sensor device of this embodiment, the upper silicon film comprises: a conductive single crystal silicon film contained in the sensor region and doped with impurities constituting the heater; And a peripheral silicon film included in the peripheral area and separated from the single crystal silicon film by the groove to surround the single crystal silicon film.

In another embodiment of the semiconductor gas sensor device, the sensing region may include a first pad electrically connected to the heater.

In another embodiment of the semiconductor gas sensor device, the peripheral area may include a second pad electrically connected to the gas sensor.

In another embodiment of the semiconductor gas sensor device, the gas sensor includes a sensor electrode whose one end extends into the sensing region and the other end which extends into the peripheral region, and a sensing film covering one end of the sensor electrode; One end of the sensor electrode may include a plurality of branches and the other end of the sensor electrode may be connected to the second pad.

In another embodiment of the semiconductor gas sensor device, the gas sensor may further include a sensor seed layer disposed between the sensor electrode and the sensing layer to improve sensing sensitivity. The sensor seed layer may include nickel (Ni).

In another embodiment of the semiconductor gas sensor device, the substrate may include a cavity in which a portion of the lower silicon bulk is removed to be limited to the sensing region and thermally isolate the heater from the lower silicon bulk. .

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor gas sensor device, comprising: providing a substrate having an oxide film formed between a single crystal silicon film and a silicon bulk; The single crystal silicon film is formed of a conductive single crystal silicon film; Separating the conductive single crystal silicon film to form a silicon heater and a peripheral silicon film; Forming a gas sensor disposed above the silicon heater; And removing the portion of the silicon bulk to form a cavity that thermally isolates the silicon heater from the silicon bulk.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, forming the conductive single crystal silicon film may include doping impurities into the single crystal silicon film.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, separating the conductive single crystal silicon film comprises: forming a first oxide film pattern exposing a portion of the conductive single crystal silicon film on the conductive single crystal silicon film; And removing the exposed conductive single crystal silicon film by a dry etching process using the first oxide film pattern as a mask to form a groove separating the conductive single crystal silicon film into the silicon heater and the peripheral silicon film. have.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, the substrate comprises: a sensing area including the silicon heater, the gas sensor, and the cavity; The peripheral silicon film may be included, and the sensing area may be separated from the sensing area by a recess to surround the sensing area.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, forming the gas sensor comprises: forming an insulating film on the substrate; Depositing platinum on the insulating film to form a sensor electrode; And forming a sensing layer by depositing zinc oxide covering the sensor electrode.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, the forming of the gas sensor may further include forming a sensor seed film between the sensor electrode and the sensing film by depositing nickel on the sensor electrode. have.

A method for manufacturing a semiconductor gas sensor element according to the present embodiment, comprising: removing a portion of the insulating film to form a contact hole exposing a portion of the silicon heater; Forming a first pad electrically connected to the silicon heater through the contact hole; The method may further include forming a second pad on the insulating layer, the second pad being electrically connected to the sensor electrode.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, the first and second pads may include forming at the same time as the sensor electrode.

In the method of manufacturing a semiconductor gas sensor device according to the present embodiment, the first pad may be formed on the silicon heater, and the second pad may be formed on the peripheral silicon film.

In the method of manufacturing a semiconductor gas sensor element of the present embodiment, forming the cavity comprises: forming a second oxide film pattern exposing a portion of the silicon bulk on the silicon bulk; Forming an etching hole exposing the oxide film by removing the exposed silicon bulk by dry etching using the second oxide pattern as a mask; And removing the exposed oxide film.

According to the present invention, by using the doped single crystal silicon as a micro heater and sensor membrane has an effect that can improve the durability against the stress caused by heat during the high temperature operation of more than 300 ℃. In addition, the use of the SOI substrate has the effect of minimizing the loss of heat from the heater to the lower silicon bulk.

Hereinafter, a semiconductor gas sensor device using the MEMS technology and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

Advantages over the present invention and prior art will become apparent through the description and claims with reference to the accompanying drawings. In particular, the present invention is well pointed out and claimed in the claims. However, the present invention may be best understood by reference to the following detailed description in conjunction with the accompanying drawings. Like reference numerals in the drawings denote like elements throughout the various drawings.

(Device Example)

1 is a plan view illustrating a semiconductor gas sensor device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the semiconductor gas sensor device 100 includes a substrate 101 such as a so-called silicon on insulator (SOI) wafer in which a thermal oxide film is included in single crystal silicon. The substrate 101 may include upper silicon layers 103a and 103b formed of single crystal silicon on an upper portion of the thermal oxide film, and a lower silicon bulk (refer to 104 of FIG. 16) below. The upper silicon films 103a and 103b may be divided into a silicon micro heater 103a and a peripheral silicon film 103b. The silicon micro heater 103a may be used as a membrane of the gas sensor 500. The substrate 101 may be electrically and / or structurally divided into the sensing region A and the peripheral region B by the groove 108, and the sensing region A may be surrounded by the peripheral region B. have.

In the sensing region A, the gas sensor 500 disposed on the silicon micro heater 103a with the silicon micro heater 103a made of single crystal silicon having conductivity and doped with an impurity and an insulating film 403 of FIG. 16 interposed therebetween. And a heater electrode pad 504 electrically connected to the silicon micro heater 103a through the contact hole 408 of FIG. 16 to transfer power to the silicon micro heater 103a. A bonding wire made of, for example, gold (Au) may be connected to the heater electrode pad 504. The silicon micro heater 103a may serve to heat the gas sensor 500 to a temperature necessary to increase the sensing sensitivity of the gas sensor 500 and serve as a membrane of the gas sensor 500.

The heater electrode pads 504 may be made of metal such as platinum (Pt) or platinum (Pt) / gold (Au), and a total of two heater electrodes 504 may be disposed on each side of the gas sensor 500. The gas sensor 500 may include a sensor electrode 502 and a sensing film 702 disposed on the sensor electrode 502. Two sensor electrodes 502 may be disposed, for example, and may be formed of a metal such as platinum (Pt), aluminum (Al), or gold (Au). One end of the sensor electrode 502 may have a form having a plurality of branches. The other end of the sensor electrode 502 extends to the peripheral area B and is electrically connected to the sensor electrode pad 506. The sensing layer 702 is composed of a sensor sensitive material, for example, a semiconductor material such as tin oxide (Sn), zinc (Nn), titanium (Ti), tungsten (W), iridium (Ir), or a metal oxide (MO _X ). Can be. Between the sensor electrode 502 and the sensing layer 702, a sensor seed layer (602 of FIG. 16), such as nickel (Ni), may be further included to improve sensor sensitivity.

In the peripheral area B, a sensor electrode pad 506 is disposed on the peripheral silicon film 103b with the peripheral silicon film 103b and the insulating film 403 in FIG. 16 interposed therebetween and electrically connected to the other end of the sensor electrode 502. ) May be included. The peripheral silicon film 103b may be made of single crystal silicon having conductivity by being doped with impurities like the silicon micro heater 103a. The sensor electrode pad 506 may be made of a metal such as platinum (Pt) or platinum (Pt) / gold (Au), and two connected to each of the two sensor electrodes 502 may be disposed. The sensor electrode pad 506 may be connected to a bonding wire made of, for example, gold (Au).

The above-described components have been described in that disposed on one surface, for example, the front surface of the substrate 101. The back of the substrate 101 may include a cavity 904 that thermally isolates the silicon micro heater 103a from the lower silicon bulk (see 104 in FIG. 16). The cavity 904 may be defined in the sensing area A. FIG.

In this embodiment, the SOI substrate is adopted as the substrate 101 and the single crystal silicon is used as the sensor membrane and the heater, so that the thermal durability of the gas sensor 500 can be improved.

The semiconductor gas sensor device 100 configured as described above may operate as follows. For example, when noxious gas such as COx, SOx, HCN, or H ₂ S comes into contact with the gas sensor 500, the gas is adsorbed to the sensing film 702, and the amount of gas adsorbed between the gas and the sensing film 702. The movement of electrons in proportion to is generated. At this time, since a potential barrier is formed to the conduction of electrons at the grain boundary of the detection layer 702 and this hinders the movement of electrons, the resistance of the detection layer 702 is changed. Accordingly, by measuring the resistance value of the sensing film 702, it is possible to detect the presence or absence of gas and the concentration thereof. The sensor electrode 502 transfers a change in resistance value of the sensing film 702 generated by adsorbing gas to an external circuit. The silicon micro heater 103a generates heat such that the gas sensor 500 rises to a specific temperature at which the gas sensor 500 may exhibit optimal sensitivity according to the power applied from the outside.

(Method Example)

2 to 16 illustrate a method of manufacturing a semiconductor gas sensor device according to an exemplary embodiment of the present invention, which are cross-sectional views illustrating processes of cutting the I-I line of FIG. 1.

Referring to FIG. 2, a substrate 101 is prepared. The substrate 101 may be a silicon wafer having a so-called silicon on insulator (SOI) structure in which an oxide film 106 is formed in a single crystal silicon layer. In the present specification, for convenience of description, the substrate 101 is divided into an upper silicon film 102 and a lower silicon bulk 104 formed of single crystal silicon based on the oxide film 106. The oxide layer 106 may be thermal SiO ₂ . By adopting the SOI substrate 101 in this embodiment, the oxide film 106 can prevent the heat generated from the silicon micro heater (103a in FIG. 16) from being transferred to the lower silicon bulk 104 as described below. Heat loss can be minimized.

Referring to FIG. 3, impurities, such as phosphorous oxychloride (POCl ₃ ), are doped onto the substrate 101. Accordingly, the upper silicon film 102 is changed to the upper silicon film 103 doped with phosphorus (P) to have conductivity. A portion of the lower silicon bulk 104 may be changed to the lower silicon layer 105 doped with phosphorus (P) by an impurity doping process. A process of removing an oxide film or the like that may be formed on the substrate 101 by an impurity doping process may be further performed using, for example, an aqueous hydrofluoric acid solution.

Referring to FIG. 4, an oxide film deposition process is performed on the substrate 101 to form a first upper oxide film 202 on the upper silicon film 103. The first lower oxide layer 204 may also be formed on the lower silicon layer 105 by the deposition process. The first upper oxide film 202 and the first lower oxide films 202 and 204 may be formed of, for example, a low temperature oxide film LTO. The first upper oxide film 202 may be formed to use a portion of the upper silicon film 103 as a mask required for a patterning process for manufacturing a silicon micro heater.

Referring to FIG. 5, the first upper oxide layer 202 is partially removed to form the first upper oxide layer pattern 202a. The first upper oxide layer pattern 202a may be formed by, for example, forming a photoresist pattern and a dry etching process. The first upper oxide layer pattern 202a may be used as a mask during an etching process on the subsequent upper silicon layer 103.

Referring to FIG. 6, a groove 108 is formed by removing a portion of the upper silicon layer 103 by a dry etching process using the first upper oxide layer pattern 202a as a mask. The upper silicon film 103 may be separated into the first upper silicon film 103a and the second upper silicon film 103b by the groove 108. The grooves 108 form a closed curve, and the first upper silicon film 103a surrounded by the grooves 108 may be used as a silicon micro heater. Hereinafter, for convenience, the first upper silicon film 103a will be referred to as a silicon micro heater, and the second upper silicon film 103b will be referred to as a peripheral silicon film. By the groove 108, the substrate 101 may be divided into a sensing region A including the silicon micro heater 103a and a peripheral region B including the peripheral silicon film 103b.

Referring to FIG. 7, the first upper oxide layer pattern 202a is removed by a wet etching process. The wet etching process may be performed by immersing the substrate 101 in an aqueous hydrofluoric acid solution. The first lower oxide layer 204 may also be removed by a wet etching process.

Referring to FIG. 8, an oxide film forming process is performed to form a second upper oxide film 402 covering the silicon micro heater 103a and the peripheral silicon film 103b. The second lower oxide film 404 covering the lower silicon film 105 may be formed together by the present oxide film forming process. The second upper oxide film 402 and the second lower oxide film 404 may be formed of, for example, a low temperature oxide film (LTO). The second upper oxide film 402 may fill the hole 108 to electrically isolate the silicon micro heater 103a from the peripheral silicon film 103b. The second lower oxide layer 404 may be patterned as described below to be used as a mask for forming a subsequent cavity 904 of FIG. 16.

Referring to FIG. 9, a chemical mechanical polishing process (CMP) is performed on the second upper oxide layer 402 to eliminate the step of the second upper oxide layer 402. As a result, the second upper oxide layer pattern 403 may be realized by removing the stepped portion. The second upper oxide layer pattern 403 may be used as an insulating layer capable of thermally insulating and electrically insulating the silicon micro heater 103a. Hereinafter, for convenience, the second upper oxide film pattern 403 will be referred to as an upper insulating film.

Referring to FIG. 10, the second lower oxide layer 404 is selectively removed to form a second lower oxide layer pattern 405. The second lower oxide layer pattern 405 may be formed by, for example, forming a photoresist pattern and a dry etching process. The first etching hole 407 is formed by forming the second lower oxide layer pattern 405, and a part of the lower silicon layer 105 is exposed through the first etching hole 407. The second lower oxide layer pattern 405 defining the first etching hole 407 may be used as a mask of an etching process for forming a subsequent cavity 904. Hereinafter, for convenience, the second lower oxide layer pattern 405 will be referred to as a lower insulating layer.

Referring to FIG. 11, the upper insulating layer 403 is partially removed to form the contact hole 408. A portion of the silicon micro heater 103a is exposed by the contact hole 408. The contact hole 408 may be formed by, for example, adopting a photoresist pattern forming method and a dry etching process. The contact hole 408 may be formed after, before, or simultaneously with forming the first etching hole 407.

Referring to FIG. 12, the sensor electrode 502, the sensor electrode pad 506, and the heater electrode pad 504 are formed on the upper insulating layer 403. The sensor electrode 502 and the heater electrode pad 504 are formed to be disposed on the silicon micro heater 103a, and the sensor electrode pad 506 is formed to be disposed on the peripheral silicon film 103b. The sensor electrode pad 506 is electrically connected to the sensor electrode 502. The heater electrode pad 504 is electrically connected to the silicon micro heater 103a through the contact hole 408.

The sensor electrode 502 may be formed of a metal such as platinum (Pt), aluminum (Al), or gold (Au) by adopting a lift-off process. The sensor electrode pad 506 may be formed after, before, or at the same time as forming the sensor electrode 502. As an example, the lift-off process may be adopted to form the sensor electrode 502 and the sensor electrode pad 506 simultaneously with platinum Pt. The heater electrode pad 504 may be formed after, before, or simultaneously with, forming the sensor electrode 502 and / or sensor electrode pad 506. As an example, the lift-off process may be adopted to form the sensor electrode 502, the sensor electrode pad 506, and the heater electrode pad 504 simultaneously with platinum Pt.

Referring to FIG. 13, the sensing film 702 is formed of a sensor sensitive material on the sensor electrode 502 to implement the gas sensor 500. Preferably, the sensor seed film 602 may be further formed before the sensing film 702 is formed. If the sensor seed film 602 is further formed, the reference sensor resistance is lowered compared to the case in which the sensor seed film 602 is not formed, and more electrons move for a certain gas concentration, resulting in improved sensor sensitivity. The sensor seed film 602 may be formed of, for example, nickel (Ni) having a thickness of 100 kHz. The sensing layer 702 may be formed of a semiconductor material, for example, an oxide (MO _X ) of a metal such as tin (Sn), zinc (Nn), titanium (Ti), tungsten (W), iridium (Ir), or the like. In this embodiment, the sensing film 702 may be formed of zinc oxide (NnO).

Referring to FIG. 14, a metal film 806 formed of, for example, gold (Au) may be further formed on the sensor electrode pad 506 to smoothly bond wires with the gold wire. For the same reason, a metal film 804 made of gold (Au) can be further formed on the heater electrode pad 504.

Referring to FIG. 15, the lower silicon film 105 and the lower silicon bulk 104 exposed by the first etching hole 407 may be selectively removed in a dry etching process using the lower insulating film 405 as a mask. An etching hole 902 is formed. The oxide layer 106 is exposed by the second etching hole 902. The oxide layer 106 may serve as an etch stop layer in the dry etching process.

Referring to FIG. 16, the cavity 904 is formed by removing the oxide film 106 exposed through the second etching hole 902 to implement the semiconductor gas sensor device 100. The oxide film 106 may be removed using a wet etching process. For example, the oxide film 106 may be removed by immersing the substrate 101 in an aqueous hydrofluoric acid solution. In this case, in order to protect the entire surface of the substrate 101 including the gas sensor 500 and the pads 504 and 506 from damage caused by hydrofluoric acid solution, a protective film such as a photoresist may be formed on the entire surface of the substrate 101.

The cavity 904 may have a kind of thermal isolation function that prevents heat generated in the silicon micro heater 103a from being transferred elsewhere through the lower silicon bulk 104. In addition, since the oxide film 106 is included, heat generated in the silicon micro heater 103a can be prevented from being lost to the lower silicon bulk 104. Accordingly, heat generated in the silicon micro heater 103a may be transferred to the gas sensor 500 well while minimizing heat loss.

The foregoing detailed description is not intended to limit the invention to the disclosed embodiments, and may be used in various other combinations, modifications, and environments without departing from the spirit of the invention. The appended claims should be construed to include other embodiments.

The present invention can be applied to the industry of manufacturing gas sensors using MEMS technology and the industry of detecting gas using gas sensors. Furthermore, the present invention can be applied to the ubiquitous sensor network (USN) industry, such as healthcare modules (systems) including U-healthcare.

1 is a plan view showing a semiconductor gas sensor device according to an embodiment of the present invention.

2 to 16 illustrate a method of manufacturing a semiconductor gas sensor device according to an exemplary embodiment of the present invention, which is a cross-sectional view of the process taken along line II of FIG. 1.

Claims (24)

A substrate having an oxide film disposed between an upper silicon film and a lower silicon bulk, and a cavity from which a portion of the lower silicon bulk is removed to expose a portion of the upper silicon film; A silicon heater composed of the upper silicon film and generating heat by receiving power; And A gas sensor disposed on an upper portion of the silicon heater to receive heat generated from the silicon heater, the sensor electrode being covered with a sensing film, and sensing a gas by a change in resistance value of the sensing film; Semiconductor gas sensor element comprising a. The method of claim 1, And the upper silicon film comprises a conductive single crystal silicon film doped with an impurity. The method of claim 1, And the cavity is formed under the silicon heater to thermally isolate the silicon heater from the lower silicon bulk. The method of claim 1, The sensor electrode is disposed above the silicon heater with an insulating film interposed therebetween; And The sensing film is a semiconductor gas sensor device, characterized in that consisting of a sensor sensitive material covering the sensor electrode. The method of claim 4, wherein The gas sensor is: And a sensor seed film disposed between the sensor electrode and the sensing film to improve sensing sensitivity. The method of claim 5, The sensor seed film is a semiconductor gas sensor device, characterized in that containing nickel (Ni). A substrate having an oxide film between the silicon film and the silicon bulk; A sensing region occupying a portion of the substrate and including a gas sensor utilizing a portion of the silicon film as a sensor membrane, and a heater constituting the sensor membrane and providing heat to the gas sensor; And A peripheral region occupying another portion of the substrate and separated from the sensor region by a groove formed by removing a portion of the silicon film; Semiconductor gas sensor element comprising a. The method of claim 7, wherein And the sensing region is electrically isolated from the peripheral region by the groove and surrounded by the peripheral region. The method of claim 7, wherein The silicon film is: A conductive single crystal silicon film included in the sensor region and doped with impurities constituting the heater; And And a peripheral silicon film included in the peripheral area and separated from the single crystal silicon film by the groove to surround the single crystal silicon film. The method of claim 7, wherein The sensing region may include a first pad electrically connected to the heater. The method of claim 7, wherein And the peripheral area includes a second pad electrically connected to the gas sensor. The method of claim 11, The gas sensor is: A sensor electrode having one end extending into the sensing region and the other end extending into the peripheral region and a sensing layer covering one end of the sensor electrode; One end of the sensor electrode comprises a plurality of branches and the other end of the sensor electrode, the semiconductor gas sensor device, characterized in that connected to the second pad. The method of claim 12, The gas sensor is: And a sensor seed film disposed between the sensor electrode and the sensing film to improve sensing sensitivity. The method of claim 13, The sensor seed film is a semiconductor gas sensor device, characterized in that containing nickel (Ni). The method of claim 7, wherein The substrate is: And a cavity which is partially removed from the silicon bulk and is formed in the sensing region and thermally isolates the heater from the silicon bulk. Providing a substrate having an oxide film formed between the single crystal silicon film and the silicon bulk; The single crystal silicon film is formed of a conductive single crystal silicon film; Separating the conductive single crystal silicon film to form a silicon heater and a peripheral silicon film; Forming a gas sensor on top of the silicon heater; And Removing a portion of the silicon bulk to form a cavity that thermally isolates the silicon heater from the silicon bulk; A method of manufacturing a semiconductor gas sensor element comprising. The method of claim 16, Forming the conductive single crystal silicon film is: A method of manufacturing a semiconductor gas sensor device comprising doping an impurity into the single crystal silicon film. The method of claim 16, Separating the conductive single crystal silicon film is: Forming a first oxide film pattern on the conductive single crystal silicon film to expose a portion of the conductive single crystal silicon film; And Removing the exposed conductive single crystal silicon film by a dry etching process using the first oxide film pattern as a mask to form a groove separating the conductive single crystal silicon film into the silicon heater and the peripheral silicon film; A method of manufacturing a semiconductor gas sensor element comprising. The method of claim 16, Forming the gas sensor is: Forming an insulating film on the substrate; Depositing platinum on the insulating film to form a sensor electrode; And Depositing zinc oxide covering the sensor electrode to form a sensing film; A method of manufacturing a semiconductor gas sensor element comprising. The method of claim 19, Forming the gas sensor is: Depositing nickel on the sensor electrode to form a sensor seed film between the sensor electrode and the sensing film. The method of claim 19, Removing a portion of the insulating film to form a contact hole exposing a portion of the silicon heater; Forming a first pad electrically connected to the silicon heater through the contact hole; And Forming a second pad on the insulating film, the second pad being electrically connected to the sensor electrode; A method of manufacturing a semiconductor gas sensor element further comprising. The method of claim 21, And manufacturing the first and second pads at the same time as the sensor electrode. The method of claim 21, And the first pad is formed on the silicon heater, and the second pad is formed on the peripheral silicon film. The method of claim 16, Forming the cavity is: Forming a second oxide film pattern on the silicon bulk to expose a portion of the silicon bulk; Forming an etching hole exposing the oxide film by removing the exposed silicon bulk by dry etching using the second oxide pattern as a mask; And Removing the exposed oxide film; A method of manufacturing a semiconductor gas sensor element comprising.

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