JP2005268660A - Infrared array sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform always stable temperature measuring by rationally and effectively utilizing a condenser lens which is originally equipped in a sensor, and by lessening any influence of an environmental temperature change while suppressing a raise of manufacturing cost as well as a deterioration of manufacturing yield. <P>SOLUTION: A plurality of rows of sensor arrays 6 are formed by making infrared measuring sensor elements 5 on the same plane of a silicon substrate 4 in a length and breadth matrix. A plurality of temperature compensating elements 7 are seriately made at the silicon substrate 4 portion adjacent to the sensor elements 5 residing at each end portion of the sensor arrays 6. There is formed an optical shielding unit 9 inhibiting an infrared incidence at a position corresponding to the temperature compensating elements 7 of a light receiving mirror 3 respectively having a pierced hole 8 for the infrared incidence at positions corresponding to light receiving sections 5a of the infrared measuring sensor elements 5. The light receiving mirror 3 having this optical shielding unit 9 is configured to be closely laminated on the silicon substrate 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention, for example, measures the surface temperature distribution of various objects such as human bodies, switchboards, and air conditioners, or checks the aging of buildings such as buildings and viaducts, diagnoses the deterioration of insulation, and further checks the temperature of food and clothing. The present invention relates to an infrared array sensor used for measuring a thermal insulation effect. Specifically, a plurality of infrared measuring sensor elements are formed in a vertical and horizontal matrix on the same plane of a semiconductor substrate to form a multi-row sensor array, and infrared rays emitted from the object to be measured are incident on the sensor array. Is used to measure the temperature of a plurality of points on the surface of the object to be measured and to display the surface temperature distribution on the object to be measured by superimposing the measured temperature data and a visible image taken by a CMOS image sensor. The present invention relates to an infrared array sensor.

  In this type of general infrared array sensor, in order to reduce disturbance noise caused by changes in the ambient temperature where the object to be measured exists, a temperature compensating element is provided separately from the infrared measuring sensor element. By correcting the output of the sensor element for measurement with the output from the element for temperature compensation, the influence when the environmental temperature changes is reduced, and stable infrared measurement can be performed.

  By the way, as an infrared array sensor provided with the temperature compensation element, conventionally, through holes are formed in a vertical and horizontal matrix form from the infrared incident surface side in a semiconductor substrate such as a silicon substrate, and the through holes are formed on the infrared non-incident surface side. While bolometer-type infrared measurement sensor elements are fabricated and arranged, concave portions are formed in a matrix form in a vertical and horizontal matrix at positions adjacent to the infrared measurement sensor elements on the non-infrared incident surface side of the semiconductor substrate. A temperature compensation element having a membrane structure similar to that of the sensor element for manufacturing is manufactured and arranged, and the concave portion formed on the infrared non-incident surface side of the semiconductor substrate is configured to prevent the incidence of infrared rays to the temperature compensation element. Those are known (for example, see Patent Document 1).

JP 2001-304973 A

  In the conventional infrared array sensor described above, since the sensor element for measurement and the element for temperature compensation are arranged adjacent to each other, even if a temperature distribution is generated in the semiconductor substrate due to a change in environmental temperature or the like, both elements Is maintained at almost the same temperature, and stable output is always obtained regardless of changes in environmental temperature, and it is possible to prevent the incidence of infrared rays into the temperature compensation element without using a special cover. .

  However, in the conventional infrared array sensor, in order to achieve the function of preventing the incidence of infrared rays to the stable output and the temperature compensating element as described above, not only the vertical and horizontal matrix-shaped through holes are formed in the semiconductor substrate, It is necessary to form vertical and horizontal matrix-shaped recesses on the infrared non-incident surface side of the substrate. Therefore, the structure of the semiconductor substrate is very complicated, and it is difficult to manufacture the substrate itself. It is also difficult to build in. In particular, for temperature compensation elements, it is necessary to individually create a plurality of elements in the corresponding recesses in order to ensure the function of preventing the incidence of infrared rays. As a result, the manufacturing process of the entire sensor becomes large and complicated. However, there has been a problem that the manufacturing cost is significantly increased and the manufacturing yield is easily deteriorated.

  The present invention has been made in view of the above circumstances, and its purpose is to increase the manufacturing cost and the manufacturing yield by rationally and effectively using the condensing lens originally provided in this type of sensor. It is an object to provide an infrared array sensor that is capable of performing stable temperature measurement with little influence of environmental temperature changes while suppressing the above.

  In order to achieve the above object, an infrared array sensor according to the present invention has a plurality of infrared sensor elements formed in a vertical and horizontal matrix on the same plane of a semiconductor substrate to form a plurality of rows of sensor arrays. In addition, an infrared array sensor provided with a condensing mirror in which infrared incident through holes are respectively formed at positions corresponding to light receiving portions of the plurality of infrared measurement sensor elements, the plurality of rows of sensor arrays A plurality of temperature compensating elements are formed in a row on the same plane as the sensor elements in the semiconductor substrate portion adjacent to the sensor elements located at each end of the sensor element, and the plurality of temperatures are formed by the condensing mirror. A light shielding part for preventing the incidence of infrared rays to the temperature compensating element is formed at a position corresponding to the compensating element, and the light collecting part having the light shielding part and the infrared incident through hole is formed. It is characterized in that the error in the semiconductor substrate which are stacked in close contact.

  In the infrared array sensor of the present invention having the above-described characteristic configuration, since the sensor element for infrared measurement and the element for temperature compensation are fabricated on the same plane of the semiconductor substrate, a temperature distribution is generated in the substrate. Even when both elements are kept at substantially the same temperature and the environmental temperature changes, the temperature measured by the sensor element can be corrected by the output from the temperature compensating element to always obtain a stable output. In addition, since the light shielding portion for preventing the incidence of infrared rays to the temperature compensating element is formed by using a part of the condensing mirror that is inherently provided in this type of sensor, a special cover is provided. It is unnecessary to form the light-shielding recesses and the through-holes in a matrix on the semiconductor substrate as in the conventional example. Accordingly, not only the configuration and manufacturing process of the semiconductor substrate itself are simple, but also the fabrication of each element on the substrate is facilitated, and the above-mentioned is achieved while significantly reducing the manufacturing cost of the entire sensor and improving the manufacturing yield. As described above, there is little influence of environmental temperature change and the like, and there is an effect that temperature measurement can always be performed accurately and stably.

  In particular, in the infrared array sensor according to the present invention, as described in claim 2, the plurality of infrared measurement sensor elements and the temperature compensation element have the same membrane structure, so that both elements are the same. It is possible to secure a stable output with few errors by making the influence when the environmental temperature changes almost equal.

  Further, in the infrared array sensor according to the present invention, as described in claim 3, a thin film having a high reflectivity is formed on the peripheral surface of the infrared incident through hole of the condensing mirror, for example, by sputtering gold. Thus, infrared rays incident on the through hole are less absorbed by the hole peripheral surface, and can be focused on the light receiving portion of the measurement sensor element to further improve the measurement accuracy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic plan view of the entire infrared array sensor 1 according to the present invention. FIG. 2 is an enlarged cross-sectional view of a main part along the line AA ′ in FIG. 1. The infrared array sensor 1 includes a light receiving chip 2. And the condensing mirror 3 superposed on this.

  On the same plane on the surface side of a silicon substrate (an example of a semiconductor substrate) 4 constituting the light receiving chip 2, as shown in FIG. 3A, m × n, for example, 8 × Seven infrared measurement sensor elements 5 are formed in a dot matrix form at regular intervals, thereby forming m rows, for example, eight rows of sensor arrays 6, and sensor arrays in each row. 6 at the end portion of the silicon substrate 2 adjacent to the m measurement sensor elements 5 positioned at the end of 6 are arranged on the same plane as each of the measurement sensor elements 5, for example, eight, for temperature compensation. Elements 7 are formed in a row.

  On the other hand, as shown in FIG. 3B, the condensing mirror 3 has m pieces at each of the positions corresponding to the light receiving portions 5a of the m × n infrared sensor elements 5 in the light receiving chip 2. Xn through-holes 8 for infrared incidence are formed, and infrared IR is incident on the temperature compensation elements 7 without holes at positions corresponding to the m temperature compensation elements 7 in the light receiving chip 2. A strip-shaped light-shielding portion 9 is formed to prevent it. Note that a thin film 18 having a high reflectivity is formed on the peripheral surface of each infrared incident through hole 8 by, for example, gold sputtering, and the infrared IR incident on the through hole 8 is absorbed by the peripheral surface. The light is condensed on the light receiving portion 5a of the measurement sensor element 5 by reducing the number.

  Then, the condenser mirror 3 configured as shown in FIG. 3B is laminated and fixed on the light receiving chip 2 in a state where the back surface thereof is in close contact with the front surface of the silicon substrate 4, so that FIG. As shown in FIG. 4, the infrared incident through hole 8 is positioned on the light receiving portion 5a of each infrared measuring sensor element 5, and each temperature compensating element 7 is covered with the light shielding portion 9 of the condenser mirror 3. Thus, the infrared array sensor 1 in a state in which the incidence of the infrared IR is prevented is configured.

  As the infrared measuring sensor element 5, an element configured as shown in FIGS. 4 and 5 is used. That is, a SiO2 thin film 10 is formed on the upper surface of the silicon substrate 4, and a thermopile sensor 12 is laminated on the SiO2 thin film 10, and an infrared ray is further formed on the thermopile sensor 12 via an insulating film 13. The absorption film 14 is laminated. The temperature compensating element 7 has the same membrane structure as the infrared measuring sensor element 5.

  The thermopile sensor 12 used for the infrared measuring sensor element 5 and the temperature compensating element 7 is made of different metals such as aluminum 12a and polysilicon 12b, and the Peltier effect is obtained by cooling the hot junction 12c. Thus, dozens of thermocouples (thermocouples) that generate thermoelectromotive force in the direction to heat the cold junction 12d are connected in series.

  Further, a signal output unit 14 and an output selection circuit 15 are formed around the light receiving chip 2, and when a predetermined voltage is supplied by the output selection circuit 15 as shown in the chip circuit diagram of FIG. The sensor element 5 and the sensor array 6 are connected via the switch SW adjacent to the infrared measuring sensor element 5 using the thermocouple 12 and the switches SW1 to SW8 provided at the end of each sensor array 6. When selected, a signal corresponding to the amount of received infrared IR light can be output from the output unit 14 to the signal detection / processing circuit 17.

  As described above, in the infrared array sensor 1 in which the infrared measurement sensor element 5 and the temperature compensation element 7 are fabricated on the same plane of the surface of the silicon substrate 4, a temperature distribution is generated in the silicon substrate 4. Even when both elements 5 and 7 are maintained at substantially the same temperature, and the environmental temperature changes, the measured temperature by the sensor element 5 can be corrected by the output from the temperature compensating element 7 to always obtain a stable output. .

  Further, the light shielding portion 9 for preventing the incidence of the infrared IR to the temperature compensating element 7 is formed by utilizing a part of the condensing mirror 3 that is originally provided in this type of infrared array sensor 1. Therefore, it is not necessary to use a special cover or the like, and it is not necessary to form light shielding recesses and through holes in a matrix on the silicon substrate 4 as in the conventional example. Not only the configuration and manufacturing process are simple, but also the elements 5 and 7 are easily formed on the silicon substrate 4.

  In particular, by configuring the infrared measuring sensor element 5 and the temperature compensating element 7 to have the same membrane structure, it is not necessary to produce a special temperature compensating element 7 and the necessary number on the light receiving chip 2. Therefore, the manufacturing cost of the entire sensor 1 can be significantly reduced and the manufacturing yield can be improved. Nevertheless, the infrared IR incident on the through-hole 8 of the condensing mirror 3 is reflected by the thin film 18 having a high reflectivity and is sufficiently absorbed by the absorption film 14 to be efficiently collected in the light receiving portion 5a of the measuring sensor element 5. Since it is possible to increase the measurement sensitivity by illuminating, the effects when both elements 5 and 7 are subjected to the same environmental temperature change are made almost equal, and accurate and stable temperature measurement with very little error. Can be performed.

  In the above embodiment, the sensor element 5 for infrared measurement and the element 7 for temperature compensation have been described using the salle pile sensor 12, but a bolometer type element may be used.

  In the above embodiment, the infrared measuring sensor element 5 and the temperature compensating element 7 are arranged in a dot matrix of 8 × 8 dots. However, the number of the arranged elements may be other than that. Of course.

1 is a schematic plan view of an entire infrared array sensor according to the present invention. It is an expanded sectional view of the principal part along the A-A 'line of FIG. The state before assembly | attachment of an infrared array sensor is shown, (a) is a schematic plan view of a light receiving chip, (b) is a schematic plan view of a condensing mirror. It is a partially cutaway perspective view of a sensor element for infrared measurement. It is a longitudinal cross-sectional view of the sensor element for infrared measurement. It is a circuit diagram of a light receiving chip.

Explanation of symbols

1 Infrared array sensor 3 Condensing mirror 4 Silicon substrate (semiconductor substrate)
DESCRIPTION OF SYMBOLS 5 Sensor element for infrared measurement 5a Light-receiving part 6 Sensor array 7 Temperature compensation element 8 Through-hole for infrared incidence 9 Light-shielding part 12 Thermopile sensor 14 Infrared absorption film 18 High reflectivity thin film IR Infrared

Claims (3)

A plurality of infrared measuring sensor elements are formed in a vertical and horizontal matrix on the same plane of the semiconductor substrate to form a plurality of rows of sensor arrays and correspond to light receiving portions of the plurality of infrared measuring sensor elements. Infrared array sensor provided with a condensing mirror in which a through-hole for infrared incidence is formed at each position,
A plurality of temperature compensating elements are formed in a row on the same plane as the sensor elements in the semiconductor substrate adjacent to the sensor elements located at each end of the plurality of sensor arrays, and the light collecting mirror In the positions corresponding to the plurality of temperature compensating elements, a light shielding part for preventing the incidence of infrared rays to the temperature compensating elements is formed, and the condensing mirror having the light shielding part and the infrared incident through-holes An infrared array sensor, wherein the semiconductor substrate is stacked in close contact with the semiconductor substrate.   The infrared array sensor according to claim 1, wherein the plurality of infrared measurement sensor elements and the temperature compensation element have the same membrane structure. 3. The infrared array sensor according to claim 1, wherein a thin film having a high reflectance is formed on a peripheral surface of the infrared incident through hole of the condensing mirror.

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