JPH11211558A - Sensor and sensor array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor and sensor array allowing the thermal isolation to be taken high. SOLUTION: In an element set in a hollow state on a substrate 2, a conductive part is provide for connecting a detector 1 to the substrate 2. This allows a support leg 3 to be taken long for a region occupied by the element, hence the thermal isolation to be taken high between the element and board 2 to improve the efficiency of a thermal sensor and the sensor integration degree can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting external signals and a sensor array in which the sensors are arranged in a two-dimensional array, and more particularly to an infrared sensor for detecting infrared rays and its sensor array. It is.

[0002]

2. Description of the Related Art The development of thermal sensors typified by thermal infrared sensors is active, and in particular, fine sensors using micromachining technology are in the practical stage. Sensor functions include temperature change due to heat ray reception, electrical resistance, spontaneous polarization,
Alternatively, heat and temperature are detected by converting into physical quantities such as thermoelectromotive force. Here, in order to effectively convert a change in the amount of heat of the detection unit into a change in temperature, it is necessary to cut off heat between the detection unit and the outside world. A structure is adopted in which the area around the temperature-sensitive portion is evacuated to reduce heat transfer to the environment due to convection, and to reduce heat conduction to the substrate on which the element is formed.

FIG. 12 is a configuration diagram of an integrated sensor element disclosed in, for example, Japanese Patent Publication No. 7-508095.
In the figure, (a) is a plan view, (b) is a cross-sectional view taken along line GG ', and 117 is a detection unit (sensing area), 120 and 121.
Is a support leg, 102 is a substrate, and 114 is a detection layer. The detection unit 117 and the substrate 102 below the support legs 120 and 121 have been removed by a micromachining technique, and the detection unit 117 is held by the support legs 120 and 121 and connected to the substrate. The detection unit 117 includes the detection layer 114 and the absorption layer 11.
6 and insulating layers 112 and 113 serving as support layers. The temperature of the detection unit 117 rises by receiving the heat ray incident on the detection unit 117. The heat ray is detected by converting the temperature rise into an electric signal by the detection layer 114 which is a thermosensitive element. The electric signal is guided to the substrate with the conductive layer above the support legs 120 and 121, and the signal is obtained through a processing circuit (not shown) or the like. The structure of this prior art is based on the detection unit 11.
7 is a structure provided for improving the heat insulating property of the substrate. The detection unit 117 is lifted off the substrate to reduce the heat transmission path. The transmission path to the substrate here is the supporting legs 120 and 121, and each supporting leg is long,
The heat insulating property is improved by using the leg material which is thin and has little heat conduction.

[0004]

In the conventional sensor element, the size of the element is an area α indicated by a dashed line surrounded by the substrate removing holes 140 and 150. Within this area,
Although it is possible geometrically to make the support legs longer and thinner by the method shown heretofore, this structure is determined by the limitations of microfabrication technology represented by, for example, semiconductor fabrication technology. It is impossible to take a long time.
Also, making the support legs 120 and 121 extremely thin is
The mechanical strength of the support leg itself is reduced, which makes it difficult to form a gap and reduces reliability. further,
If the area occupied by the elements is reduced and a large number of elements are incorporated in the same area, there is a problem that if the same design guideline is used, the heat insulation characteristics deteriorate and the desired performance cannot be obtained. there were. Further, since the area where the sensing layer 114 can be formed is smaller than the area α indicated by the dashed line occupied by the sensor element, the area where the sensor element is occupied becomes extremely narrow when the area occupied by the sensor element is reduced. There were also points.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a sensor configuration which enables improvement of heat insulation characteristics and furthermore, a large number of sensors and high-density integration by reducing the size of sensor elements. The purpose is to gain.

[0006]

According to a first aspect of the present invention, there is provided a sensor provided on a substrate, supporting a detection unit for detecting a signal from the outside, and extracting a signal from the detection unit to the outside. In the sensor having a supporting portion provided with a conductive portion, the detecting portion and the substrate are insulated from each other by the supporting portion formed to meander in a rectangular shape in the normal direction of the substrate surface.

A sensor according to a second aspect of the present invention is the sensor according to the first aspect, wherein the detecting unit is disposed above the substrate.

According to a third aspect of the present invention, in the second aspect, the detecting section is disposed above the supporting section.

A sensor according to a fourth aspect of the present invention is the sensor according to the first aspect, wherein the detection unit is disposed in substantially the same plane of the substrate.

A sensor according to a fifth aspect of the present invention is the sensor according to the first aspect, wherein at least the substrate below the detecting portion has a groove corresponding to a region of the detecting portion, and the supporting portion is arranged in a depth direction of the substrate. Is what is done.

A sensor according to a sixth aspect of the present invention is the sensor according to the fifth aspect, wherein a groove is formed in the substrate in a region where the supporting portion and the detecting portion are formed.

A sensor according to a seventh aspect of the present invention is the sensor according to the first aspect, further comprising a signal absorbing section in the detecting section.

[0013] The sensor array according to claim 8 of the present invention is provided on a substrate, and has a detection unit for detecting an external signal, and a part of the detection unit is connected to the substrate and detected by the detection unit. In a sensor array in which a plurality of conductive parts for extracting signals to the outside are arranged in a two-dimensional array, the conductive layer is connected to the substrate at an adjacent sensor or at a further apart sensor part. Things.

According to a ninth aspect of the present invention, in the sensor array according to the ninth aspect, one sensor has a plurality of conductive portions, and at least one of the plurality of conductive portions is electrically connected to a substrate having conductivity. It is what is connected.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view showing a configuration of a sensor according to an embodiment of the present invention, and FIG.
2A is a sectional view, FIG. 2A is a sectional view taken along the line AA ′ in FIG. 1, FIG. 2B is a sectional view taken along the line BB ′ in FIG.
FIG. 2C is a cross-sectional view taken along the line CC ′ in FIG. In the drawing, reference numeral 1 denotes a detection unit having a detection layer 7 on a base layer 5 (lower layer), 2 denotes a substrate, and 3 denotes a conductive layer 6 on the base layer 5 (lower layer).
The supporting leg 8 has a connecting portion. The detection unit 1 is supported by two support legs 3 extending three-dimensionally from the substrate, and includes a detection layer 7, electrodes of a conductive layer 6 for extracting signals from the detection layer 7, and a base layer 5. The base layer 5 is a layer that supports the structure of the detection unit 1 and the support leg 3, and includes a lower layer 5a and an upper layer 5b. The support leg 3 includes a conductive layer 6 and a base layer 5. In these figures, three layers of aerial wiring are shown in addition to the detection area. Each support leg 3 is adjacent at its end a support leg 3,
The connection unit 8 is connected to the detection unit 1 or the substrate 2. By forming the support legs 3 not only in the in-plane direction of the substrate as in the conventional case but also in the normal direction as in the present embodiment, the total extension of the support legs can be made sufficiently long. Further, according to the present invention, since the sensor element can be manufactured without making the supporting legs for supporting the detecting portion thinner as in the related art, the impact reliability and storage reliability of the sensor are satisfied. A sensor that can be manufactured.

The configuration of the embodiment shown here is manufactured, for example, as follows. FIG. 3 is a diagram showing a manufacturing method described below. Silicon oxide for protection is laminated on a silicon substrate having a signal processing circuit of the sensor. The substrate 2 is not particularly limited as long as it is made of a material that can withstand the removal of the last dissolved layer 9 or has a protective layer 13. On this substrate 2, for example, a dissolution layer 9 made of silicon is laminated. In order to connect to the substrate 2, a hole is provided in the dissolving layer 9 at the location of the connection portion 8, a lower layer 5a of the base layer 5 made of silicon oxide is provided, and a hole for electrical connection to the substrate is provided in the connection portion 8 ( FIG. 3 (a). Next, a conductive layer 6 made of, for example, chromium metal is laminated, and the conductive layer 6 is adjusted to the shape shown in FIG. Further, an upper layer 5b of the base layer 5 made of, for example, silicon nitride is laminated (FIG. 3B). The base layer 5 and the conductive layer 6 serving as the support legs 3 are shaped into a desired shape (FIG. 3C). Thereafter, the dissolving layer 9, the base layer 5, and the conductive layer 6 can be laminated as necessary, and the shape can be adjusted, whereby the laminated supporting leg 3 can be formed. As the detection unit 1, a support layer made of silicon oxide, a detection layer 7 such as a metal, an oxide, a nitride, etc., whose electric resistance changes according to a temperature change, and a conductive layer 6 as an electrode are provided, and the shape shown in FIG. Prepare. Here, silicon nitride is added last as a protective layer (FIG.
(D)). Finally, the silicon provided as the dissolution layer 9 is removed by exposing it to xenon fluoride gas (FIG. 3E).
Through these steps, the structure shown in FIG. 1 can be obtained.

As described above, the sensor element manufactured according to the present invention has a substantial support leg length several times as large as that manufactured by a conventional planar method even in a region of several tens of microns square, for example. Alternatively, longer lengths can be obtained. Even if the area occupied by the sensor is fixed, the heat insulation characteristics can be improved. Further, even when a large number of sensor elements are provided on the same area by narrowing the area occupied by one sensor, the sensor element can be manufactured without deterioration of the heat insulating property or with further improvement. Also, by providing the detection unit 1 on the top surface,
The area in which the sensor layer 7 can be formed can be made larger than the area occupied by the sensor. In particular, when the sensor is made smaller or the number of elements can be increased, the area of the sensor layer can be made larger, so that the sensor layer is hard to be processed into a fine shape. There is an advantage that can be applied.

Embodiment 2 FIG. FIG. 4 corresponds to a partial top view of the sensor shown in the first embodiment, and is a top view of a layer of the support leg 3 and corresponds to FIG. 2B relating to the first embodiment. . The structure is such that the support leg 3 extends in the plane and is bent as compared with the first embodiment. This bent structure is also found in the prior art, and makes more efficient use of the in-plane area. Since the length of the support legs is increased in the plane, the number of layers of the support legs to be stacked can be reduced.

The materials described in the first and second embodiments are applied to silicon-based semiconductor fine processing which is considered to be mature, and are easily manufactured industrially. The main use of silicon, silicon oxide, or silicon nitride as the support legs has the advantage that a fine and inexpensive sensor can be easily manufactured by applying semiconductor fine processing technology.

Embodiment 3 FIG. 5 shows another example of the sensor having the stacked support legs. FIG. 5A shows a configuration having the flat-type detection unit 1 and the support legs 3 in which a plurality of support legs 3 are provided. By using this structure, it is possible to improve the heat insulation characteristics. .

Here, for example, in a thermal infrared sensor, the light receiving area affects the performance, as is well known. When the infrared optical system and the object to be measured are determined, the intensity of incident radiation is constant at the area density, so that a performance proportional to the light receiving area can be obtained. For this reason, the aperture ratio improving layer 10
Can also be provided. FIG. 5B shows a structure in which the absorption layer 11 is provided in the first embodiment. By providing the detection unit 1 on the uppermost surface as described above, the area where the detection layer can be formed does not become narrower than the sensor area. Also in this embodiment, the absorption layer 11 can be effectively formed in many areas of the sensor area, and the performance as a sensor is further improved.

Embodiment 4 Further, as shown in FIG. 6, the detection layer 7 is positioned on
Also, the structure protruding on the upper surface is effective. As a material, as is well known as a micromachining technology, silicon oxide is used as a dissolution layer, silicon nitride, silicon, or another combination as a structure / support leg, or an organic layer as a dissolution layer and an inorganic layer as a structure layer. The material of the structure, such as use, is not limited to the first embodiment.

Embodiment 5 FIG. 7 shows Embodiment 5 of the present invention.
FIG. 3 is a configuration diagram of a sensor according to FIG. FIG. 7A shows FIG. 7C.
FIG. 7B is a cross-sectional view taken along a broken line DD ′ in FIG.
It is sectional drawing by the EE 'broken line in (c). In this sensor element, the support leg 3 is manufactured by being embedded in the substrate 2. An example of the manufacturing means is as follows.

For example, a closed rectangular groove is formed in the substrate 2 by deep groove processing. A dissolution layer 9 made of silicon oxide is formed thereon.
Is provided. The dissolving layer 9 is prepared so as to remain only in the groove and the lower part of the detecting unit 1. After that, the base layer 5, the conductive layer 6, and the detection layer 7 are laminated, and their shapes are adjusted. The base layer 5 and the conductive layer 6 are formed by a vapor deposition type film forming method so as to be easily attached to the groove side walls. By adjusting the shape of the base layer 5, a part of the dissolved layer of silicon oxide is exposed on the re-surface. In this state, the sensor element is completed by removing silicon oxide mainly using hydrofluoric acid. In FIG. 7A, the dissolving layer 9 has been removed to form the gap 4. Support leg 3 is substrate 2
The structure extends into the substrate 2 according to the groove provided therein. The area for forming the support leg can be made smaller than the length of the support leg. Thus, a structure in which the support legs are not shortened due to the effective use of the sensor area or the downsizing of the sensor can be achieved. Also in this structure, it is effective to provide the above-described opening enhancement layer 10 for improving the performance as a radiation detection type sensor.

Embodiment 6 FIG. FIG. 8 shows Embodiment 6 of the present invention.
FIG. 3 is a cross-sectional view of a sensor configuration according to the present invention. Also in this case, a method for melting the substrate is applied as in the fifth embodiment. Here, it is manufactured by a processing method without crystal anisotropy, and when silicon is used as a substrate material, processing can be performed using a solution mainly composed of xenon fluoride or nitric hydrofluoric acid. A groove is provided so as to surround a region where the support leg 3 for obtaining heat insulating properties is provided. This groove may be formed, for example, in the same manner as that formed when forming the support leg 3, or may be provided anew. The groove is formed so as to surround the sensor portion having the gap, and determines the shape of the gap. In the above-described method for producing a gap, the substrate is processed without any choice. Therefore, if the sensor is formed into multiple elements in a narrow area, the gaps of adjacent elements are connected, and the sensor cannot be held on the substrate.
The closed groove on the outer periphery is provided for stopping the processing. With this structure, a gap is formed by removing a part of the substrate, and in the sensor to be formed, the above-described processing method which provides good characteristics as a method for forming the gap can be applied. Can be easily reduced in size.

Embodiment 7 FIG. 9 shows Embodiment 7 of the present invention.
FIG. 2 is a cross-sectional view and a top view of a sensor configuration according to the first embodiment. FIG. 9 (a)
FIG. 10 is a sectional view taken along a broken line FF ′ in FIG. 9B. In this sensor, the substrate is limited to a crystalline one. For example, it is a silicon substrate having a well-known (100) orientation on its surface. After grooves are formed in the substrate 2, the base layer 5, the conductive layer 6, the detection layer 7, and the like are laminated and shaped, a substrate removal hole 12 parallel to the {110} direction of the substrate is opened until the substrate 2 is reached. In this state, when the substrate 2 is immersed in, for example, a potassium hydroxide solution, the processing is stopped when the specific crystal orientation plane is exposed. This is a well-known crystal anisotropic processing method shown in the prior art. This completes a sensor element with good thermal separation. The dissolving layer 9 required in the fourth embodiment becomes unnecessary, and the sensor can be manufactured. As the substrate, other materials such as magnesium oxide can be used, and a substrate having phosphoric acid as a main component can obtain a similar structure.

Embodiment 8 FIG. FIG. 10 is a top view showing a configuration of a sensor array according to Embodiment 8 of the present invention. FIG. 11 shows a sensor array produced by arraying sensors according to the conventional invention. In the figure, reference numerals 20 and 21 are portions connected to the substrate. In the conventional embodiment, a support leg 3 having a detection unit 1 and a conductive unit (not shown) for extracting a signal from the detection unit is provided in an area occupied by the sensor. The structure has a problem that it is difficult to improve the heat insulating property. In FIG. 10 of the eighth embodiment,
Arrayed sensors not only in each sensor area but also adjacent,
Alternatively, the supporting leg (conductive portion of the supporting leg) is connected to the substrate by a sensor unit farther away from the sensor unit. With such a configuration, the heat insulation characteristics can be improved.

Further, when the substrate has conductivity and each sensor can be grounded in common, one of the substrate connecting portions can be used.
For example, it is effective to connect the electric connection portion 21 to the substrate in FIG. That is, the number of wirings can be reduced, and the same operation can be performed even if the peripheral circuits for performing the array operation are driven in the same manner as the conventional one.

In the above embodiment, the sensor is exemplified by an infrared sensor. However, a temperature sensor for detecting radiation other than infrared rays and other physical quantities, a sensor for measuring the degree of vacuum in a vacuum region, and a flow sensor Needless to say, it can be applied to such applications.

[0030]

As described above, according to the first aspect of the present invention, a detection unit provided on a substrate and detecting an external signal is supported, and a signal detected by the detection unit is transmitted to an external device. In the sensor having a support portion having a conductive portion for taking out to the, since the support portion formed to meander in a rectangular shape in the normal direction of the substrate surface, the detection portion and the substrate were insulated, Further, since the detection unit is disposed above the substrate or the support unit, and the detection unit is disposed substantially in the plane of the substrate, the heat insulation characteristics are improved, and the sensor can be reduced. Further, in the above structure, the support portion is arranged in the depth direction of the substrate. Since the above structure is adopted, the support portion can be longer than before, the heat insulating property is improved, and the support is provided on a flat surface. Also, the in-plane occupancy of the support portion is reduced, and the sensor can be reduced in size. Further, in the above structure, since the detection unit is further provided with the signal absorption unit, the signal is efficiently captured, and the performance as a sensor is improved.

According to the second aspect of the present invention, a detecting unit provided on the substrate for detecting an external signal and a part of which is connected to the substrate and detected by the detecting unit are provided. And a conductive part for taking out a signal to the outside.
In a sensor array in which a plurality of sensor elements are arranged in a two-dimensional array, the conductive portion is connected to the substrate at an adjacent sensor or a sensor portion at a further distant location, so that heat insulation characteristics are improved and the degree of integration of elements is increased. It becomes possible. In addition, in the above structure, one sensor has a plurality of conductive portions, and at least one of the plurality of conductive portions is electrically connected to a conductive substrate, so that wiring in the substrate is easy. It is possible to manufacture a simple sensor.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sensor configuration according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view and a top view of a sensor configuration according to the first embodiment of the present invention.

FIG. 3 is a diagram related to a method for manufacturing a sensor configuration according to the first embodiment of the present invention;

FIG. 4 is a top view of a sensor configuration according to Embodiment 2 of the present invention.

FIG. 5 is a sectional view of a sensor configuration according to Embodiment 3 of the present invention.

FIG. 6 is a sectional view showing a configuration of a sensor according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view and a top view of a sensor configuration according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view of a sensor configuration according to Embodiment 6 of the present invention.

FIG. 9 is a sectional view and a top view of a sensor configuration according to a seventh embodiment of the present invention.

FIG. 10 is a top view of a sensor array configuration according to an eighth embodiment of the present invention.

FIG. 11 is a top view showing the arrangement of a conventional sensor array.

FIG. 12 is a top view and a sectional view of a conventional sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Detection part, 2 Substrate, 3 Support leg, 4
Air gap, 5 base layer, 5a lower layer of base layer, 5b
Upper layer of substrate layer, 6 Conductive layer, 7 Detection layer, 8
Connection part, 9 dissolution layer, 10 opening enhancement layer, 1
1 Absorption layer, 12 Substrate removal hole, 13 Protective layer, 20 Substrate connection, 21 Substrate electrical connection.

Claims (9)

[Claims] 1. A sensor provided on a substrate and supporting a detection unit for detecting a signal from outside, and having a support unit provided with a conductive unit for extracting a signal detected by the detection unit to the outside, A sensor, wherein the detection unit and the substrate are insulated from each other by the support unit, which is meandering in a rectangular shape in a direction normal to a substrate surface. 2. The sensor according to claim 1, wherein the detection unit is disposed above the substrate. 3. The sensor according to claim 2, wherein the detection unit is disposed above the support unit. 4. The sensor according to claim 1, wherein the detection unit is disposed in substantially the same plane of the substrate. 5. The sensor according to claim 1, wherein at least the substrate below the detection section has a groove corresponding to the area of the detection section, and the support section is arranged in the depth direction of the substrate. . 6. The sensor according to claim 5, wherein a groove is formed in the substrate in a region where the support part and the detection part are formed. 7. The sensor according to claim 1, further comprising a signal absorbing unit in the detecting unit. 8. A detecting unit provided on a substrate for detecting a signal from the outside, and a conductive unit partially connected to the substrate and extracting a signal detected by the detecting unit to the outside. A sensor array in which a plurality of sensors are arranged in a two-dimensional array, wherein the conductive layer is connected to the substrate at an adjacent sensor or a sensor unit at a further distant place. 9. The sensor according to claim 8, wherein one sensor has a plurality of conductive portions, and at least one of the plurality of conductive portions is electrically connected to a conductive substrate. Sensor array.