[DESCRIPTION]

[invention Title]

TILT SENSOR AND MANUFACTURING METHOD THEREOF [Technical Field] The present invention relates, in general, to a tilt sensor for sensing a tilt and converting the tilt into an electrical signal and a method of manufacturing the tilt sensor, and, more particularly, to a tilt sensor and method of manufacturing the tilt sensor, which use the convection of air.

[Background Art]

A tilt sensor is a means for sensing the degree to which a certain object tilts due to gravity, that is, an angle. That is, a tilt sensor is a device for sensing a tilt and converting the tilt into an electrical signal, and the range of application fields thereof is so wide that the tilt sensor has been used in fields such as Factory Automation (FA) , robots, pollution prevention, various types of disaster protection devices, transport means such as vehicles or airplanes, and precise measurement and automation, such as space and ocean reconnaissance and medical technology, as well as various types of electric home appliances.

However, since tilt sensors, which have been developed to date, have a large size, it is difficult to apply such a tilt sensor. Further, sensors that use gas as a medium employ a method of measuring a tilt by heating air

and sensing variation in the temperature distribution of air corresponding to a tilt. However, there is a limitation in that, when such a sensor is heated, air is expanded, so that the expanded air is not isolated from external air, and thus the reaction speed and sensitivity of the sensor are deteriorated. [Disclosure] [Technical Problem]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a tilt sensor, in which low costs and small size are realized, and which has excellent reactivity and sensitivity to variation in a tilt. Another object of the present invention is to provide a method of manufacturing the tilt sensor in bulk through a simplified manufacturing process.

[Technical Solution]

In accordance with an aspect of the present invention to accomplish the above objects, there is provided a tilt sensor, comprising a sealing wall for providing an inner space sealed from an outside; a convection generation unit for circulating air, existing in the inner space provided by the sealing wall, in a certain direction by convection by heating a first region of the inner space and cooling a second region of the inner space, the convection generation unit being arranged to a first side of the inner space; and

a temperature detection unit for detecting a temperature difference corresponding to varying temperature distribution of air and outputting a current corresponding to the detected temperature difference to an outside when the temperature distribution of air, circulated by convection by the convection generation unit, varies according to variation in tilt, the temperature detection unit being arranged to a second side of the inner space so that the temperature detection unit is opposite the convection generation unit.

Preferably, the convection generation unit of the tilt sensor may comprise a first thermoelectric semiconductor device configured such that a P-type semiconductor region and an N-type semiconductor region are respectively formed on a first surface of a first semiconductor substrate, a first metal wire part is formed by connecting first side surfaces of the P-type semiconductor region and the N-type semiconductor region to each other via a metal wire, and second metal wire parts are formed by connecting metal wires to respective second side surfaces of the P-type semiconductor region and the N- type semiconductor region.

Preferably, the convection generation unit may comprise power electrodes electrically connected to the second metal wire parts in order to be externally supplied with power, and the first thermoelectric semiconductor device may be operated such that, when power is externally

supplied through the power electrodes, the first metal wire part generates heat and the second metal wire parts absorb heat, thus circulating air existing in the inner space in a certain direction by convection. Preferably, the temperature detection unit of the tilt sensor may comprise a second thermoelectric semiconductor device configured such that a P-type semiconductor region and an N-type semiconductor region are respectively formed on a first surface of a second semiconductor substrate, a first metal wire part is formed by connecting first side surfaces of the P-type semiconductor region and the N-type semiconductor region to each other via a metal wire, and second metal wire parts are formed by connecting metal wires to respective second side surfaces of the P-type semiconductor region and the N- type semiconductor region.

Preferably, the temperature detection unit may comprise sensor electrodes electrically connected to respective second metal wire parts to output current to an outside, and the second thermoelectric semiconductor device may generate a current corresponding to a temperature difference and output the current to an outside through the sensor electrodes when a temperature difference occurs between the first metal wire part and the second metal wire parts according to variation in tilt of the tilt sensor.

Preferably, the sealing wall of the tilt sensor may be configured such that insulating layers are formed on

both surfaces of a third semiconductor substrate, the third semiconductor substrate is etched through both surfaces thereof, and the convection generation unit and the temperature detection unit are respectively bonded around openings formed through etching, thus providing the inner space .

Preferably, the sealing wall may comprise sensor connection parts for connecting the current output from the temperature detection unit to the outside, and power connection parts configured to be externally supplied with power and to connect the power to the convection generation unit.

In accordance with a second aspect of the present invention to accomplish the above objects, there is provided a method of manufacturing a tilt sensor, comprising the steps of (a) completing a convection generation unit by sequentially forming a first thermoelectric semiconductor device and power electrodes on a first semiconductor substrate; (b) completing a temperature detection unit by sequentially forming a second thermoelectric semiconductor device and sensor electrodes on a second semiconductor substrate; (c) completing a sealing wall by performing etching to pass through a third semiconductor substrate and forming an opening, the sealing wall for enabling the convection generation unit and the temperature detection unit to be bonded thereto and performing sealing; and (d) bonding the convection

generation unit and the temperature detection unit to the sealing wall so that the first thermoelectric semiconductor device and the second thermoelectric semiconductor device are arranged to sides of the inner space sealed by the sealing wall and are opposite each other, thus performing sealing.

Preferably, step (a) of the method may comprise the steps of (al) forming insulating layers on both surfaces of the first semiconductor substrate; (a2) respectively forming a P-type semiconductor region and an N-type semiconductor region on a first surface of the first semiconductor substrate; (a3) forming a first metal wire part by connecting first side surfaces of the P-type semiconductor region and the N-type semiconductor region to each other via a metal wire, and forming second metal wire parts by connecting metal wires to second side surfaces of the P-type semiconductor region and the N-type semiconductor region, thus forming the first thermoelectric semiconductor device; and (a4) forming power electrodes that extend from the second metal wire parts and are connected to metal wires.

Preferably, step (b) of the method may comprise the steps of (bl) forming insulating layers on both surfaces of the second semiconductor substrate; (b2) respectively forming a P-type semiconductor region and an N-type semiconductor region on a first surface of the second semiconductor substrate; (b3) forming a first metal wire

part by connecting first side surfaces of the P-type semiconductor region and the N-type semiconductor region to each other via a metal wire, and forming second metal wire parts by connecting metal wires to second side surfaces of the P-type semiconductor region and the N-type semiconductor region, thus forming the second thermoelectric semiconductor device; and (b4) forming sensor electrodes that extend from the second metal wire parts and are connected to metal wires. Preferably, step (c) of the method may comprise the steps of (cl) forming insulating layers on both surfaces of the third semiconductor substrate; and (c2) etching the third semiconductor substrate through both surfaces thereof, and forming a wall for enabling the convection generation unit and the temperature detection unit to be bonded thereto and performing sealing.

[Advantageous Effects]

A tilt sensor according to the present invention is constructed such that a first thermoelectric semiconductor device is formed in an inner space sealed by a sealing wall, and a heating source and a cooling source for causing convection are provided, so that the problem of air expansion and air outflow are solved, and the convection of air can be more smoothly conducted, thus improving reactivity and sensitivity to variation in tilt.

Further, a tilt sensor according to the present invention is constructed such that a plurality of second

thermoelectric semiconductor devices is provided and arranged to sense forward/backward tilt variation as well as left/right tilt variation, thus measuring tilts in four directions, including left and right directions and forward and backward directions .

Furthermore, the present invention is advantageous in that a semiconductor manufacturing process can be used, and a convection generation unit and a temperature detection unit, which are the components of the present invention, can be manufactured through the same manufacturing process, thus contributing to the realization of low-cost and small tilt sensors. [Description of Drawings]

FIG. 1 is a plan view of a tilt sensor according to a first embodiment of the present invention;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIGS. 3 (a) to 3 (c) are plan views showing the components of the tilt sensor according to the first embodiment of the present invention;

FIGS . 4 and 5 are diagrams showing operation relative to variation in tilt according to a first embodiment of the present invention;

FIG. 6 is a process flow diagram showing a method of manufacturing the convection generation unit and the temperature detection unit of the tilt sensor according to the first embodiment of the present invention;

FIG. 7 is a process flow diagram showing a method of manufacturing the sealing wall of the tilt sensor according to the first embodiment of the present invention;

FIG. 8 is a process flow diagram showing a process for bonding the convection generation unit, the temperature detection unit, and the sealing wall according to a first embodiment of the present invention;

FIG. 9 is a plan view of a tilt sensor according to a second embodiment of the present invention; FIGS. 10 (a) to 10 (c) are plan views showing the components of the tilt sensor according to the second embodiment of the present invention;

FIG. 11 is a sectional view taken along line A-A of FIG. 9; and FIG. 12 is a sectional view taken along line B-B of FIG. 9. [Best Mode]

Hereinafter, the structure of a tilt sensor and method of manufacturing the tilt sensor according to embodiments of the present invention will be described in detail with reference to the attached drawings. (Embodiment 1)

FIG. 1 is a plan view of a tilt sensor according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A of FIG. 1, and FIG. 3 is a plan view showing respective components of the tilt sensor according to the first embodiment of the present

invention. Hereinafter, the tilt sensor according to the first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

As shown in FIGS. 1 and 2, a tilt sensor 1 according to the first embodiment includes a convection generation unit 100, a temperature detection unit 200, and a sealing wall 300. The overall operation of the tilt sensor 1 according to the present invention is described in brief. As shown in FIG. 2, the convection generation unit 100 and the temperature detection unit 200 are arranged to the opposite sides of the inner space sealed by the sealing wall 300. The convection generation unit 100 is configured to circulate air, existing in the inner space sealed by the sealing wall 300, by convection. The temperature detection unit 200 detects a temperature difference corresponding to varying temperature distribution and outputs current corresponding to the temperature difference to the outside of the tilt sensor when the temperature distribution of air, circulated by convection by the convection generation unit 100, varies according to variation in tilt, thus measuring the tilt. Here, the temperature detection unit 200 and the convection generation unit 100 are preferably arranged to be symmetrical relative to each other in the direction of gravity. For example, the convection generation unit 100 is arranged in the lower portion of the tilt sensor and the temperature detection unit 200 is arranged in the upper portion thereof, so that air,

ascending due to heating performed by the convection generation unit 100, can reach the temperature detection unit 200. Further, the sealing wall 300 must be configured to seal both the convection generation unit 100 and the temperature detection unit 200 in order to prevent internal air from flowing out from the inner space or external air from flowing into the inner space. Hereafter, the above- described components will be described in detail below.

As shown in FIG. 2 and FIG. 3 (a), the convection generation unit 100 is arranged to one side of the inner space of the sealing wall 300, and includes power electrodes 110 and a first thermoelectric semiconductor device 120. The first thermoelectric semiconductor device 120 is externally supplied with power through the power electrodes 110 and is configured to heat part of the air present inside the sealing wall 300 and to cool the remaining part of the air using the supplied power, thus circulating the air inside the sealing wall 300 in a certain direction by convection. The power electrodes 110 are components that are externally supplied with power. The first thermoelectric semiconductor device 120 is operated such that, when power is externally supplied through the power electrodes 110, the first metal wire part 125 of the first thermoelectric semiconductor device generates heat and the second metal wire parts 126 thereof absorb heat, thus circulating the air inside the sealing wall 300 in a certain direction by

convection.

The power electrodes 110 are provided by forming metal wires extending from the first side surfaces of the second metal wire parts 126. That is, as shown in FIG. 3 (a), the power electrodes 110 are formed to extend from the second metal parts 126 and to have the same width as the second metal wire parts 126, and are made of the same material as the second metal wire parts 126. The power electrodes 110 and the second metal wire parts 126 can be functionally distinguished in such a way that the power electrodes 110 are components required to be externally supplied with power, and the second metal wire parts 126 are components required to absorb heat.

In the case of the first thermoelectric semiconductor device 120, insulating layers 122 are formed on both surfaces of a first semiconductor substrate 121, a P-type semiconductor region 123 and an N-type semiconductor region 124 are sequentially formed on one surface of the first semiconductor substrate 121, the first metal wire part 125 is formed by connecting the first side surfaces of the P- type semiconductor region 123 and the N-type semiconductor region 124 to each other via a metal wire, and the second metal wire parts 126 are formed by connecting metal wires to respective second side surfaces of the P-type semiconductor region 123 and the N-type semiconductor region 124, by which the first thermoelectric semiconductor device 120 is completed. Here, the P-type semiconductor

region 123 and the N-type semiconductor region 124 may be made of P-type polysilicon and N-type polysilicon, respectively. Further, the first thermoelectric semiconductor device 120 may be formed to have a linear shape or a "U" shape. However, the first metal wire part 125 is arranged at the center of the convection generation unit 100, and the second metal wire parts 126 are arranged at the border of the convection generation unit 100. This is intended to generate heat at the center of the convection generation unit 100 and to absorb heat at the border thereof. Through this construction of the first thermoelectric semiconductor device, the Peltier effect is realized.

The Peltier effect is described below with reference to FIG. 4 (a) . That is, it indicates a phenomenon in which, when the first side surfaces of two types of regions, that is, the P-type semiconductor region 123 and the N-type semiconductor region 124, are connected to each other via a metal wire to form the first metal wire part 125, and then power is connected to the second metal wire parts 126 to apply current, the first metal wire part 125 generates heat and the second metal wire parts 126 absorb heat. With reference to FIG. 2, the Peltier effect is described below. When power is externally supplied through the power electrodes 110, the first metal wire part 125 generates heat, and the second metal wire parts 126 absorb heat to thus cause cooling. When the polarities of power are

changed, a heating region and a cooling region may be changed.

In the tilt sensor according to the first embodiment, the first thermoelectric semiconductor device 120 is arranged so that heat is generated at the first metal wire part 125, which is the center of the inner space of the sealing wall 300, and cooling occurs at the second metal wire parts 126, which are the borders of the inner space of the sealing wall 300. Therefore, convection, caused by the first thermoelectric semiconductor device 120, occurs, so that enclosed air ascends due to the generation of heat at the center of the inner space of the sealing wall 300, and the enclosed air descends due to cooling at the border of the inner space of the sealing wall 300. Through this technical construction, the present invention can solve the problem of air expansion afflicting the conventional tilt sensor, which has only a heating part. Further, in the tilt sensor according to the present invention, a thermoelectric semiconductor device capable of simultaneously performing heating and cooling is implemented through a semiconductor manufacturing process, thus enabling the mass production of tilt sensors.

As shown in FIGS. 2 and 3 (c) , the temperature detection unit 200 includes sensor electrodes 210 and a second thermoelectric semiconductor device 220, and is arranged to another side of the inner space of the sealing wall 300 to be opposite the convection generation unit 100.

When the temperature distribution of air, circulated by convection by the convection generation unit 100, varies according to variation in tilt, the temperature detection unit 200 detects the varying temperature distribution of internal air and outputs current corresponding to the detected temperature distribution to the outside of the tilt sensor.

The sensor electrodes 210 are configured to output current to the outside, and are provided by forming metal wires extending from the second metal wire parts 226 of the second thermoelectric semiconductor device 220. As shown in FIG. 2, since the sensor electrodes 210 are not exposed to the outside, sensor connection parts 320 formed in the sealing wall 300, which will be described later, are required in order to transfer the current output from the sensor electrodes 210 to the outside.

When the temperature distribution of air, circulated by convection by the convection generation unit 100, varies according to variation in tilt, and the difference between the temperatures of the first metal wire part 225 and the second metal wire parts 226 of the second thermoelectric semiconductor device 220 occurs due to the varying temperature distribution of air, the second thermoelectric semiconductor device 220 generates current corresponding to the temperature difference, and outputs the current to the outside through the sensor electrodes 210.

In the case of the second thermoelectric

semiconductor device 220, a P-type semiconductor region 223 and an N-type semiconductor region 224 are sequentially formed on one surface of a second semiconductor substrate 221, the first metal wire part 225 is formed by connecting the first side surfaces of the P-type semiconductor region 223 and the N-type semiconductor region 224 to each other via a metal wire, and the second metal wire parts 226 are formed by connecting metal wires to respective second side surfaces of the P-type semiconductor region 223 and the N- type semiconductor region 224, by which the second thermoelectric semiconductor device 220 is completed. Here, the P-type semiconductor region 223 and the N-type semiconductor region 224 may be made of P-type polysilicon and N-type polysilicon, respectively. Further, the second thermoelectric semiconductor device 220 may be formed to have a linear shape or a "U" shape. The first metal wire part 225 is arranged at the center of the temperature detection unit 200, and the second metal wire parts 226 are arranged at the border of the temperature detection unit 200. Through the second thermoelectric semiconductor device, having the above construction, the Seebeck effect is realized.

Referring to FIG. 4 (b) , the Seebeck effect indicates the phenomenon in which, when a temperature difference exists between the first metal wire part 225 and the second metal wire parts 226 of two types of regions, that is, the P-type semiconductor region 223 and the N-type

semiconductor region 224, an electromotive force is generated. When a voltmeter is connected, as shown in FIG. 4 (b) , the generated electromotive force can be measured.

Hereinafter, the operating principles of the first embodiment are described below with reference to FIGS. 2 and 5. When power is externally supplied through the power electrodes 110, the first metal wire part 125 of the first thermoelectric semiconductor device 120 generates heat, and the air surrounding the first metal wire part 125 expands and then ascends, as shown in FIG. 5. The ascending air comes into contact with the first metal wire part 225 of the second thermoelectric semiconductor device 220, and moves to the second metal wire parts 226 of the second thermoelectric semiconductor device 220, and thereafter descends through the air cooled by the second metal wire parts 126 of the first thermoelectric semiconductor device 120. In this case, when a tilt is 0°, the temperatures of air existing around the first metal wire part 225 and the second metal wire parts 226 of the second thermoelectric semiconductor device 220 differ due to the convection occurring inside the sealing wall 300, as shown in FIG. 5 (a). When the temperature difference occurs between both bonding portions occurs due to the different temperatures of air, the current corresponding to the temperature difference is output to the outside through the sensor electrodes 210 and the sensor connection parts 320. When a tilt occurs, the convection pattern of air changes, as

shown in FIG. 5 (b) , so that the temperature difference between the first metal wire part 225 and the second metal wire parts 226 of the second thermoelectric semiconductor device 220 appears in a form different from the case of FIG. 5 (a) , and a current value corresponding to the temperature difference is also output as a different value.

That is, the current value obtained when a tilt is 0° is greater than that obtained when a tilt occurs.

In this way, the current corresponding to variation in tilt is output to the outside through the sensor electrodes 210 and the sensor connection parts 320.

The sealing wall 300 functions to provide a certain space in which thermal transfer or convection, caused by the convection generation unit 100, can be smoothly performed, and to prevent external air from flowing into the inner space of the sealing wall 300 and internal air from flowing out from the inner space. Here, as shown in FIGS. 2 and 3 (b) , the sealing wall 300 is implemented using a wall 310 formed in such a way that insulating layers 312 are formed on both surfaces of a third semiconductor substrate 311 and the third semiconductor substrate 311 is etched through both surfaces thereof. The convection generation unit 100 and the temperature detection unit 200 are bonded to the wall 310, and thus sealing is performed. In this case, the insulating layers 312 are typically made of silicon oxide films SiC> ₂ . Such silicon oxide films Siθ ₂ are formed on the bonding surfaces of the wall 310 and the

convection generation unit 100 _λ and the bonding surfaces of the wall 310 and the temperature detection unit 200, thus increasing thermal insulation between the convection generation unit 100 and the temperature detection unit 200. The sealing wall 300 may further include a power connection part (not shown) configured to be externally- supplied with power and to electrically connect the power to the convection generation unit 100. As described above, since the power electrodes 110 of the convection generation unit are formed to be exposed to the outside, the power connection part is not required. However, unlike the first embodiment, the power connection part may be required according to the change in a structure. The power connection part (not shown) may be formed in a portion on one surface of the wall 310 bonded to the convection generation unit 100, and may be formed using a metal wire so that it is electrically connected to the power electrodes 110 of the convection generation unit 100.

Further, the sealing wall 300 includes the sensor connection parts 320 for connecting the current output from the temperature detection unit 200 to the outside. In this case, the sensor connection parts 320 are formed at certain portions on one surface of the wall 310 bonded to the temperature detection unit 200, and are formed using metal wires so that they are electrically connected to the sensor electrodes 210 of the temperature detection unit 200. Accordingly, the current output through the sensor

electrodes 210 of the temperature detection unit 200 is transferred to the outside through the sensor connection parts 320 formed on one surface of the wall 310. However, the sealing wall 300 is not necessarily provided with the sensor connection parts 320, as is the first embodiment. Unlike the first embodiment, when the temperature detection unit 200 of FIG. 3 (c) is formed to have the same size as the convection generation unit 100 of FIG. 3 (a), the sensor electrodes 210 of the temperature detection unit 200 are exposed to the outside, so that it may be possible to output current to the outside without the aid of the sensor connection parts 320. Further, it is preferable to form the wall 310 to have a uniform thickness. However, the wall 310 may not be formed to have a uniform thickness according to an etching method. The reason for this is that the thickness of the sealing wall is not greatly important unless it influences the convection of enclosed air because the principal purpose of the sealing wall 300 is to enclose air. Hereafter, with reference to FIGS. 6 to 8, the process for manufacturing the tilt sensor according to the first embodiment of the present invention is described in detail below. The process for manufacturing the tilt sensor can be mainly divided into four processing steps . First, as shown in FIG. 6, the first thermoelectric semiconductor device 120 and the power electrodes 110 are sequentially formed on the first semiconductor substrate

121, and thus the convection generation unit 100 is completed at step SlOO. Next, the second thermoelectric semiconductor device 220 and the sensor electrodes 210 are sequentially formed on the second semiconductor substrate 221, and thus the temperature detection unit 200 is completed at step S200. Next, as shown in FIG. 7, etching is performed to pass through the third semiconductor substrate 311, and thus the sealing wall 300, which enables the convection generation unit 100 and the temperature detection unit 200 to be bonded thereto and which performs sealing, is completed at step S300. Finally, as shown in FIG. 8, the convection generation unit 100 and the temperature detection unit 200 are bonded to the sealing wall 300, and thus sealing is performed at step S400. Hereinafter, steps SlOO, S200, and S300 are described in detail below.

Step SlOO is composed of five processing steps, as shown in FIG. 6.

First, as shown in FIG. 6 (a), the insulating layers 122 are formed on both surfaces of the first semiconductor substrate 121. Each of the layers is typically made of a silicon oxide film (SiO ₂ ) formed through an oxidation process at step SIlO. Next, as shown in FIG. 6 (b) , polysilicon is deposited, and is then patterned at step S120. As shown in FIG. β(c), P-type and N-type ion injection processes are sequentially performed using the patterned polysilicon as a mask, so that the P-type

semiconductor region 123 and the N-type semiconductor region 124 are respectively formed at step S130. Next, as shown in FIG. 6 (d) , the first thermoelectric semiconductor device 120 is provided in such a way that the first metal wire part 125 is formed by forming a metal wire for connecting the first side surfaces of the P-type semiconductor region 123 and the N-type semiconductor region 124 to each other, and the second metal wire parts 126 are formed by forming metal wires at the second side surfaces of the P-type semiconductor region 123 and the N- type semiconductor region 124, and the power electrodes 110 are provided in such a way that metal wires extending from the first side surfaces of the second metal wire parts 126 are formed at step S140. Here, the metal wires are formed through photo etching after metal material is deposited. Finally, as shown in FIG. 6(e), the bottom surface of the first semiconductor substrate 121 is etched, and thus the bottom surface of the convection generation unit 100 is formed at step S150. Such a bottom surface etching process may be typically performed through wet etching. Through this bottom surface etching process, as shown in FIG. 6(e), the first semiconductor substrate 121 has the shape of a membrane, that is, a thin film. This shape is obtained by removing the silicon substrate placed below the first thermoelectric semiconductor device 120, so that heat loss caused by the silicon substrate is minimized. This is because the thermal conductivity of the silicon substrate

is high. Therefore, the insulation performance of the inner space formed by the first thermoelectric semiconductor device 120 and the sealing wall 300 can be improved.

Step S200 is the process for completing the temperature detection unit 200, and is similar to the process for manufacturing the convection generation unit 100 at step SlOO of FIG. β. Step S200 is performed to form the second thermoelectric semiconductor device 220 on the second semiconductor substrate 221 and form the sensor electrodes 210 on the second semiconductor substrate 221. Further, the second thermoelectric semiconductor device 220 is formed in the shape of a membrane, similar to the first thermoelectric semiconductor device 120. This is required to improve the insulation performance of the inner space formed by the second thermoelectric semiconductor device 220 and the sealing wall 300.

Step S300 is a process for completing the sealing wall 300, and is composed of three steps, as shown in FIG. 7. First, as shown in FIG. 7 (a) , the insulating layers 312 are formed on both surfaces of the third semiconductor substrate 311 at step S310. Next, as shown in FIG. 7 (b) , the third semiconductor substrate 311 is etched through both surfaces thereof, and thus the wall 310 for enabling the convection generation unit 100 and the temperature detection unit 200 to be bonded thereto and performing sealing is formed at step S320. At the above-described step S300, the sealing wall 300 is formed using the third

semiconductor substrate 311, such as a silicon substrate. The sealing wall 300 may be formed using various types of material, such as plastic material or polymer, according to the purpose of use or manufacturing costs thereof. Finally, as shown in FIG. 7 (c) , the metal wires are formed at portions bonded to the temperature detection unit 200 on one surface of the wall 310, and thus the sensor connection parts 320 are provided at step S330. The sensor connection parts 320 are electrically connected to the sensor electrodes 210 of the temperature detection unit 200, and are provided to output current output from the sensor electrodes 210 to the outside.

The tilt sensor according to the first embodiment may be manufactured using a silicon substrate, as described above, but may be manufactured using a glass wafer or a quartz wafer according to the manufacturing costs or the purpose of use. When thermoelectric devices are formed on the glass wafer, it is possible to perform thermal insulation, and there is no need to form insulating layers (refer to 122 (or 222) of FIG. 6) on the substrate, as in the case of the first embodiment, because the thermoelectric devices are electrical nonconductors .

In this way, the tilt sensor 1 according to the first embodiment of the present invention is configured to have the simplest shape using only two thermoelectric semiconductor devices, so that the tilt sensor can be manufactured to have a small size. The tilt sensor is also

provided with a cooling source, as well as a heating source, as a source for causing convection, thus more smoothly performing convection while solving the problem of air expansion. Further, there is an advantage in that the first and second thermoelectric semiconductor devices 120 and 220 can be manufactured using the same manufacturing process.

(Second embodiment)

FIG. 9 is a plan view showing a tilt sensor according to a second embodiment of the present invention, FIG. 10 is a plan view showing the components of the tilt sensor according to the second embodiment, FIG. 11 is a sectional view taken along line A-A of FIG. 9, and FIG. 12 is a sectional view taken along line B-B of FIG. 9. Hereinafter, with reference to FIGS. 9 to 12, the construction of the tilt sensor according to the second embodiment of the present invention will be described in detail below.

As shown in FIGS. 9, 11 and 12, a tilt sensor 1 according to the second embodiment of the present invention 1 includes a convection generation unit 100, a temperature detection unit 200, and a sealing wall 300. A description of components identical to those of the first embodiment is omitted.

First, as shown in FIG. 10 (a) and FIG. 12, the convection generation unit 100 includes a plurality of first thermoelectric semiconductor devices 120 and power electrodes 110, which are formed on a first semiconductor

substrate 121. When power is externally supplied through the power electrodes 110, each of the first thermoelectric semiconductor devices 120 is operated such that the first metal wire part 125 thereof generates heat and the second metal wire parts 126 thereof absorb heat, thus circulating air existing inside a sealing wall 300 in a certain direction by convection.

Unlike the first embodiment, the plurality of first thermoelectric semiconductor devices 120 is provided and is connected to each other. The first thermoelectric semiconductor devices 120, connected in series in this way, are arranged so that the first metal wire parts 125 generate heat at the center of the convection generation unit 100, and the second metal wire parts 126 absorb heat at the border of the convection generation unit 100. The overall shape of the series-connected first thermoelectric semiconductor devices 120 can be formed in a radial shape. In this case, the center portion of the radial shape is arranged at the center of the convection generation unit 100 and the border part of the radial shape is arranged at the border of the convection generation unit 100.

As shown in FIG. 10 (a) , the overall shape of the series-connected first thermoelectric semiconductor devices 120 is a cross (+) . The first metal wire parts 125 of the first thermoelectric semiconductor devices 120 are arranged such that heat is generated at the center portion 125A of the cross shape, as shown in FIG. 10 (a) . Further, the

second metal wire parts 126 of the first thermoelectric semiconductor devices 120 are arranged such that heat is absorbed at the end side portions 126A of rectangles extending from four respective sides of a rectangle placed at the center portion 125A in the direction of respective borders of the convection generation unit 100, as shown in FIG. 10 (a) . Here, each of the first thermoelectric semiconductor devices 120 can be formed to have a "U" shape . When the first thermoelectric semiconductor devices 120 are connected in series in this way, the amount of generated heat and the amount of absorbed heat increase in proportion to the number of series-connected first thermoelectric semiconductor devices, so that it is possible to actively cause the convection of air and to change the amount of convection and the circulation pattern according to the number and shape of first thermoelectric semiconductor devices connected in series.

Next, as shown in FIG. 10 (c) , the temperature detection unit 200 includes a plurality of second thermoelectric semiconductor devices 220 and a plurality of sensor electrodes 210. As shown in FIGS. 10 (a) and 10 (c) , the plurality of second thermoelectric semiconductor devices 220 is arranged such that the first metal wire parts 225 thereof are opposite the first metal wire parts 125 of the first thermoelectric semiconductor devices 120 and the second metal wire parts 226 thereof are opposite

the second metal wire parts 126 of the first thermoelectric semiconductor devices 120. Here, the second thermoelectric semiconductor devices 220 are divided into a plurality of groups according to the arrangement region of the temperature detection unit 200, are electrically connected to each other in respective groups, and generate currents for respective groups according to variation in tilt. Respective sensor electrodes 210 are separately provided to output the currents generated for respective groups . For example, as shown in FIG. 10 (c) , the second thermoelectric semiconductor devices 220 extend from four sides of the temperature detection unit 200 toward the center of the temperature detection unit 200 for respective groups, so that the shapes of respective groups become rectangles . Further, the sensor electrodes 210 include four pairs of electrodes, as shown in FIG. 10 (c) .

The plurality of second thermoelectric semiconductor devices 220 is divided into four groups corresponding to four sides of the temperature detection unit 200, and four pairs of sensor electrodes 210 respectively output currents, generated by the second thermoelectric semiconductor devices 220 divided into the four groups, to the outside of the tilt sensor.

In this case, the second thermoelectric semiconductor devices 220, divided into four groups, are electrically connected in series to each other, as shown in FIG. 10 (c) , and are formed to have the shapes of rectangles extending

from the four sides of the temperature detection unit 200 toward the center thereof, and respective rectangular shapes are arranged to correspond to the cross shape of the first thermoelectric semiconductor devices 120 of FIG. 10 (a). That is, four sets 225A, each composed of the first metal wire parts 225 of the temperature detection unit 200, are opposite the center portion 125A, and four sets 226A, each composed of second metal wire parts 226, are opposite the four end side portions 126A. The currents, generated by the second thermoelectric semiconductor devices 220 divided into four groups in this way, are respectively output to four pairs of sensor electrodes 210. Here, each of the second thermoelectric semiconductor devices 220 is formed to have a "U" shape. As described above, when the second thermoelectric semiconductor devices 220 are connected in series, the current output through the sensor electrodes 210 increases in proportion to the number of second thermoelectric semiconductor devices connected in series, and the amount of current changes according to the number and shape of second thermoelectric semiconductor devices connected in series.

According to the second embodiment, the plurality of first thermoelectric semiconductor devices 120 is provided to actively perform the convection of air enclosed by the sealing wall 300, thus improving the sensitivity of the sensor, and the second thermoelectric semiconductor devices 220 are divided into four groups and are then arranged,

thus outputting current values corresponding to forward/backward tilt, as well as left/right tilt. [industrial Applicability]

As described above, a tilt sensor according to the present invention is a device for sensing a tilt and converting the tilt into an electrical signal, and can be usefully used in fields, such as Factory Automation (FA) and precise measurement and automation, such as robots, as well as various types of electric home appliances.