JP2011191215A - Thermopile type infrared sensor and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and downsized thermopile type infrared sensor which can accurately perform measurement with good sensitivity by reducing an influence of infrared rays on a cold junction of a thermopile. <P>SOLUTION: In a thermopile forming part, only a predetermined region containing a side of the cold junction is covered with an infrared ray-shielding layer. The infrared ray-shielding layer has a configuration being connected with a metal pedestal and a metal. Heat of the infrared ray-shielding layer is effectively dissipated. Therefore, the configuration is such that the temperature of the infrared ray-shielding layer is unlikely to propagate to the side of the cold junction, temperature rise of the cold junction can be prevented, the configuration is simple and the production cost is lowered, and the configuration can be downsized with assuring strength of a sensor element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an infrared sensor that detects infrared rays emitted from a heat source and converts them into electrical signals, and more particularly, a thermopile having a thermopile in which a plurality of thermocouples that reflect temperature changes in electromotive force of contact points of different metals are connected in series. Type infrared sensor.

  As is well known, a thermopile infrared sensor has a thermopile formed by connecting a plurality of thermocouples connected to each other end portions of dissimilar metals formed on a substrate as contacts. Thereby, a temperature change due to infrared radiation absorption is detected (output) as a thermoelectromotive force using the Seebeck effect. In general, in a thermopile infrared sensor, each contact of a thermopile that is under the influence of heat conduction of a heat absorber that receives infrared light is called a hot contact. Further, each contact of the thermopile that is less affected by the heat conduction of the heat absorber is referred to as a cold junction. The cold junction is a junction that becomes a reference temperature when the temperature changes.

JP 2002-156283 A Japanese Patent Laid-Open No. 5-126663

  FIG. 13 is a cross-sectional view showing a main part of a conventional thermopile infrared sensor 100. The thermopile infrared sensor 100 has a thermopile on an insulating layer 102 that is difficult to transfer heat supported by, for example, a P-type single crystal Si substrate 101. The thermopile is configured by connecting in series a plurality of thermocouples in which ends of different metals are connected as contact points. The hot junction 108 side of the thermopile is near the center of the insulating base material 102, and the lower substrate is etched away in view of heat capacity. An infrared absorbing layer 113 that receives infrared rays from the outside is disposed in the vicinity of the hot junction 108 side. Further, the cold junction 107 side of the thermopile is a contact that becomes a reference temperature when the temperature changes. The cold junction 107 side is near the periphery of the insulating layer 102, and the lower substrate 101 is configured to support the insulating layer 102. The thermopile is covered with a protective film 105, and an infrared absorption layer 113 is disposed thereon. When the infrared absorption layer 113 receives infrared rays and changes its temperature, the temperature of the hot junction 108 also changes accordingly. The cold pile 107 side of the thermopile is covered with a protective film 105, and an infrared shielding layer 106 is disposed thereon. The infrared shielding layer 106 reflects the infrared ray irradiated to the cold junction 107 side or absorbs the infrared ray, thereby preventing the cold junction 107 from directly rising in temperature due to the infrared ray. The electromotive force (output voltage) generated between the hot junction 108 and the cold junction 107 depends on the temperature difference between the contacts between the hot junction and the cold junction.

  However, part of the infrared rays to be absorbed by the infrared absorption layer 113 reaches the cold junction 107 side, and a part of the infrared rays is absorbed by the infrared shielding layer 106, the temperature of the infrared shielding layer 106 rises, and the heat is increased. There has been a problem that the substrate 101 and the cold junction 107 are heated. Thereby, an unexpected temperature rise of the cold junction 107 appears, and the temperature difference between the contacts between the actual hot junction and the cold junction becomes small. As a result, the electromotive force (output voltage) in the thermopile is reduced, leading to problems such as a reduction in sensitivity and measurement errors.

  The present invention has been made in consideration of the above-mentioned circumstances, reduces the influence of infrared rays of the cold junction in the thermopile, can be measured more sensitively and accurately, and can be created in a simple process at a low cost and smaller. An object is to provide a thermopile infrared sensor.

The present invention employs the following means in order to solve the above problems.
An infrared sensor according to the present invention includes an electrically insulating film, a thermopile disposed on one side of the film, an infrared shielding layer that covers a part of the film, and a pedestal that supports the film. , Wherein the film is made of a resin-based material, and the thermopile is partly or entirely embedded in the film, and has an outer periphery from the center side of the film. The infrared shielding layer covers the thermopile disposed on the outer peripheral portion of the film on one surface side of the film, and extends from the outer peripheral portion of the film. The surface of the infrared shielding layer facing the film from the outer peripheral portion on the other surface of the film Together are arranged to definitive peripheral part portion disposed extending from the film, and wherein the connecting the film and the infrared shielding layer and thermally.

  According to the configuration of the present invention, since the thermopile is buried in the film, the surface of the light receiving portion of the buried portion of the film becomes a flat surface. Therefore, it is possible to provide an infrared sensor capable of increasing the temperature uniformity of the light receiving unit and providing a stable output. Furthermore, since heat dissipation due to the unevenness of the film light receiving portion can be minimized, the sensitivity can be further improved.

  According to the present invention, since the infrared sensor is mounted on the wiring board or the like via the pedestal portion, the thermocouple is spaced from the wiring board or the like. Therefore, the thermal insulation of the thermopile can be ensured.

  Moreover, according to this invention, since the infrared shielding layer is provided, the infrared rays irradiated from the object to be measured are not directly irradiated to the cold junction by the infrared shielding layer. Thereby, the temperature rise of the cold junction by infrared rays can be prevented, and the sensitivity of the thermopile can be improved. In addition, since the pedestal portion is connected to the infrared shielding layer with metal, the infrared rays emitted from the object to be measured are radiated by the metal pedestal portion connected to the infrared shielding layer. Thereby, the temperature rise of the cold junction by infrared rays can be prevented, and the sensitivity of the thermopile can be further improved.

  Further, according to the present invention, the sensor element is made of metal by adopting a structure in which the metal pedestal for radiating the heat of the cold junction and the metal pedestal for radiating the heat of the infrared shielding layer are integrated. Covering the outer periphery of the pedestal can reduce the manufacturing cost with a simple structure, while ensuring the strength of the sensor element, minimizing the temperature of the cold junction by infrared rays, and improving the sensitivity of the thermopile Can be made. Moreover, the same structure can be simply applied by creating the metal part which connects an infrared shielding layer and a base part to the infrared sensor produced by the other process.

In the infrared sensor according to the present invention, the thermopile includes a plurality of film-like thermocouples joined in series along the surface direction of the film, and the film-like thermocouples are two kinds of film-like things joined together. One end side of the first film-like material in the one film-like thermocouple, and one end side of the second film-like material in the one film-like material. And a film-shaped thermocouple adjacent to the one film-shaped thermocouple, and the other film-side thermocouple adjacent to the one film-shaped thermocouple. The cold junction which connected the other end side of the said 2nd film-form material in a pair is arrange | positioned in the outer peripheral part of the said film, It is characterized by the above-mentioned.
According to the present invention, since the light receiving portion (thermocouple hot junction forming region) of the infrared sensor is formed of a resin film having low thermal conductivity, the thermocouple hot junction and other regions are used. A large temperature difference can be taken. Therefore, the sensitivity of the infrared sensor can be further increased.

  According to the present invention, since the temperature difference between the hot junction of the film-shaped thermocouple in which the temperature rises due to light reception and the cold junction paired therewith can be increased, the output voltage can be further increased. . Moreover, since the film-like thermocouple is buried in the resin film, the temperature uniformity of the light receiving portion (around the hot junction of the film-like thermocouple) is increased, and a thermopile infrared sensor capable of providing a stable output can be provided. .

  In the infrared sensor according to the present invention, the infrared shielding layer covers the cold junction on one surface side of the film, and the pedestal portion is disposed on the outer peripheral portion on the other surface side of the film. It is characterized by being arranged in the part which was made. Further, the pedestal portion is made of a metal deposited by a plating method. According to the present invention, for example, when a film-like thermocouple is adopted for the thermopile, heat is easily radiated from the cold junction of the film-like thermocouple that needs to avoid temperature rise as much as possible through the pedestal. Therefore, since the temperature rise of the cold junction can be prevented, the temperature difference between the hot junction and the cold junction is increased, and the electromotive force of the film thermocouple can be increased. As a result, an infrared sensor with high sensitivity (output) can be provided.

  The infrared sensor according to the present invention is characterized in that a conductive layer is formed on the other surface of the film and the surface of the infrared shielding layer facing the film, and the pedestal is deposited from the conductive layer. To do. Further, in the infrared sensor according to the present invention, the material deposited by the plating method is a material selected from nickel, gold, platinum, rhodium, iron, palladium, copper, or a material mainly composed of a material selected from these materials. It is characterized by being.

  The infrared sensor according to the present invention is characterized in that the infrared shielding layer is an infrared reflecting layer. According to this invention, the infrared rays irradiated from the measurement object are reflected by the infrared reflection layer. The heat generated by absorbing part of the heat is dissipated by the base part having a structure in which the metal base part that dissipates the heat of the cold junction and the metal base part that dissipates the heat of the infrared shielding layer are integrated. . Thereby, while preventing the temperature rise of the cold junction by infrared rays, the temperature rise of an infrared reflective layer can be suppressed.

  The infrared reflective layer is made of a metal deposited by a plating method. According to this invention, the convenience in a manufacturing process is acquired by using the same metal material for the said base part and the said infrared reflective layer.

  The infrared sensor according to the present invention is characterized in that the infrared shielding layer is an infrared absorption layer. According to this invention, infrared rays irradiated from the object to be measured are absorbed by the infrared absorption film. The heat generated by the absorption is dissipated by the base part having a structure in which the metal base part that radiates the heat of the cold junction and the metal base part that radiates the heat of the infrared shielding layer are integrated. Thereby, while preventing the temperature rise of the cold junction by infrared rays, the error by the secondary radiation from the peripheral member at the time of mounting, etc. can be reduced.

  The infrared sensor according to the present invention is characterized in that the infrared absorption layer is made of a metal having high infrared absorption such as gold black or NiCr alloy. According to this invention, a high infrared absorptance can be obtained.

  Further, the infrared shielding layer covers a part of the film through an insulating layer formed on a part of the film.

In addition, the infrared sensor according to the present invention is characterized in that an infrared absorption layer is formed in a portion where the hot junction on the other surface side of the film is disposed. According to this invention, infrared rays irradiated from the object to be measured are absorbed by the infrared absorption film. Therefore, the temperature of the hot junction side of the thermocouple can be quickly raised by the infrared rays absorbed by the infrared absorption film. Thereby, the sensitivity of a thermopile can further be improved.
The pedestal is thermally bonded to the wiring board by mounting.

  An infrared sensor manufacturing method according to the present invention includes an infrared shielding layer forming step for forming an infrared shielding layer on an outer peripheral portion of a substrate, and a thermopile forming step for forming a thermopile from an upper portion of a central portion of the substrate to an upper portion of the outer peripheral portion. And a film layer forming step of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile, and a metal from an outer peripheral portion of the film to an exposed portion of the infrared shielding layer. A pedestal portion forming step for forming the pedestal portion and a peeling step for peeling the substrate are provided.

  The infrared sensor manufacturing method according to the present invention includes a peeling layer forming step of forming a peeling layer on a substrate, an infrared shielding layer forming step of forming an infrared shielding layer on an outer peripheral portion of the peeling layer, and the substrate. A thermopile forming step of forming a thermopile from the upper part of the central part to the upper part of the outer peripheral part, and a film layer forming process of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile, A pedestal forming process for forming a pedestal made of metal from an outer peripheral part of the film to an exposed part of the infrared shielding layer, and a peeling process for removing the peeling layer are provided.

  According to the present invention, the thermocouple can be buried in the film layer by forming a release layer that is easily separated from the substrate and forming a film layer on the thermocouple formed on the release layer. it can. Next, the bonded body can be easily separated from the substrate by separating the bonded body integrally with the release layer. Thereafter, by removing the release layer by means such as etching, an infrared sensor in which the thermocouple is buried in a resin film can be manufactured.

  In the infrared sensor manufacturing method according to the present invention, in the thermopile forming step, the first thin film pattern made of the first material constituting the film-like thermocouple is formed, and the film-like thermocouple is constituted. And forming a second thin film pattern to be joined to the first thin film pattern, and forming a hot junction and a cold junction as a contact point between the first thin film pattern and the second thin film pattern, respectively. A thermopile is formed on the release layer and the insulating layer.

  In addition, the infrared sensor manufacturing method according to the present invention includes an insulating layer forming step of forming an insulating layer on a central side of the substrate on the infrared shielding layer after the infrared shielding layer forming step and before the thermopile forming step. It is characterized by providing.

  Moreover, the manufacturing method of the infrared sensor which concerns on this invention forms the electroconductive layer which has electroconductivity on the said infrared shielding layer and the said film in the said base part formation process, The said base part is the said film. And deposited from a conductive layer bonded to the infrared shielding layer.

  In the infrared sensor manufacturing method according to the present invention, in the pedestal portion forming step, after forming the conductive layer, a portion formed at an end portion of the substrate of the conductive layer and a central portion of the film of the conductive layer A photoresist layer is formed in the formed portion.

  Moreover, the manufacturing method of the infrared sensor according to the present invention is characterized in that the pedestal portion is made of a metal deposited by a plating method.

  According to the present invention, the infrared shielding layer is connected to the pedestal portion made of metal and the metal, and the portion covered with the infrared shielding layer and the pedestal portion of the film can be efficiently radiated. Thereby, the temperature rise of a cold junction can be prevented. In addition, the influence of infrared rays at the cold junction in the thermopile is reduced, and more accurate and accurate measurement is possible.

It is a figure showing the thermopile type | mold infrared sensor which concerns on 1st embodiment of this invention, a thermopile formation surface direction, and a principal part cross section. It is a figure showing the thermopile formation surface direction cross section of the thermopile type infrared sensor which concerns on 1st embodiment of this invention. It is explanatory drawing which shows the process of forming a peeling layer among the processes for producing the thermopile type infrared sensor which concerns on 1st embodiment of this invention. It is explanatory drawing which shows the process of forming an infrared shielding layer among the processes for producing the thermopile type infrared sensor which concerns on 1st embodiment of this invention. It is explanatory drawing which shows the process of forming an insulating layer among the processes for producing the thermopile type infrared sensor which concerns on 1st embodiment of this invention. Of the steps for producing the thermopile type infrared sensor according to the first embodiment of the present invention, the step of forming the thin film pattern made of the first material and the thin film pattern made of the second material constituting the film thermocouple It is explanatory drawing which shows. Of the steps for manufacturing the thermopile type infrared sensor according to the first embodiment of the present invention, the step of forming a layer mainly composed of an electrically insulating resin that constitutes the light receiving portion and the like. It is explanatory drawing shown. Of the steps for producing the thermopile type infrared sensor according to the first embodiment of the present invention, the heat from the cold junction of the film thermocouple is radiated to form a metal portion for keeping the temperature of the cold junction constant. It is explanatory drawing which shows the process to do. Of the steps for producing the thermopile type infrared sensor according to the first embodiment of the present invention, the heat from the cold junction of the film thermocouple is radiated to form a metal portion for keeping the temperature of the cold junction constant. It is explanatory drawing which shows the process to do. It is explanatory drawing which shows the process of peeling a board | substrate and a peeling layer, and the process of removing a peeling layer among the processes for producing the thermopile type infrared sensor which concerns on 1st embodiment of this invention. It is a figure showing the cross section which mounted the thermopile type infrared sensor module which concerns on 1st embodiment of this invention in the wiring board. It is a figure showing the principal part cross section of the thermopile type infrared sensor which concerns on 2nd embodiment of this invention. It is a figure showing the principal part cross section of the conventional thermopile type infrared sensor.

1st Embodiment which concerns on this invention is described based on drawing.
Fig.1 (a) shows the thermopile type infrared sensor which is 1st embodiment of this invention from the thermopile formation surface direction, FIG.1 (b) is the cross section in AA in Fig.1 (a). FIG.

  As shown in FIG. 1, the thermopile infrared sensor 1 includes a plurality of film-shaped thermoelectric elements each composed of a film 2, a first thin-film thermocouple material 3, and a second thin-film thermocouple material 4. The film-shaped thermocouple is buried in the film 2.

  The pedestal portion 18 has a rectangular frame shape having a through hole in the center, and the film 2 is formed so as to cover an opening edge on one side thereof. Moreover, the conductive layer 9 is formed on the surface facing the film and the film of the infrared shielding layer. Note that the pedestal portion 18 is obtained by forming a plating layer on the conductive layer 9. That is, the pedestal portion 18 is made of metal. Further, the pedestal portion 18 is disposed from the outer peripheral portion of the film to a portion that extends from the outer peripheral portion of the film on the surface side facing the film of the infrared shielding layer. Furthermore, the base part 18 is thermally connected with the film and the infrared shielding layer. When the pedestal is formed by plating, it can be formed of a material selected from nickel, gold, platinum, rhodium, iron, palladium, copper, or a material mainly composed of a material selected from these materials.

  The film 2 is made of a material such as an ultraviolet curable epoxy-based photoresist whose main component is an electrically insulating resin, and has a rectangular shape in plan view when viewed from the thickness direction. is there. The film 2 is supported by the pedestal portion 18 on the outer peripheral side thereof and constitutes a light receiving portion that receives infrared radiation. That is, the thermopile type infrared sensor of the present embodiment has a membrane structure in which the outer peripheral portion of the film 2 is supported by the pedestal portion 18.

  FIG. 2 is a diagram in which the infrared shielding layer 6 of FIG. A region indicated by a dotted line indicates the infrared shielding layer 6.

  As shown in FIG. 2, the plurality of pairs of film thermocouples form a thermopile by alternately connecting the first thin film thermocouple material 3 and the second thin film thermocouple material 4 in series. . Specifically, each film thermocouple includes one end side of the first thin film thermocouple material 3 in one film thermocouple and one end of the second thin film thermocouple material 4 in one film thermocouple. The hot junction 8 connected to the side is disposed on the light receiving portion of the film 2, while the other end side of the first thin film thermocouple material 3 in one film thermocouple and one film thermocouple A cold junction 7 connected to the other end of the second thin film thermocouple material 4 in the film thermocouple adjacent to is disposed on the base 1 of the film 2. Thereby, the several film-like thermocouple is buried in the film 2 in the state connected in series.

  The final ends of the plurality of film-shaped thermocouples are connected to output electrodes (connection terminal portions) 14, respectively. The voltage generated in the film-shaped thermocouple is taken out by the output electrode 14 which is the final end. It is supposed to be.

  Moreover, as shown in FIG. 1, the insulating layer 5 is formed in the part by which the cold junction 7 of the surface by the side of the thermopile of a film is arrange | positioned. An infrared shielding portion 6 is formed on the insulating layer 5. Further, the infrared shielding layer is disposed so as to extend from the outer peripheral portion of the film. The insulating layer 5 is formed of, for example, an ultraviolet curable epoxy photoresist. When formed by plating, the infrared shielding layer (infrared reflective layer) can be formed of a material selected from nickel, gold, and platinum, or a material mainly composed of a material selected from these materials. When formed by sputtering, the infrared shielding layer (infrared reflective layer) can be formed of a material such as Al or Ag. The infrared shielding layer (infrared absorbing layer) can be formed of a material such as gold black when formed by a vacuum deposition method. The infrared shielding layer (infrared absorbing layer) can be formed of a material such as NiCr when formed by sputtering. In addition, when an ultraviolet curable epoxy-type photoresist is used for the material of the film 2, it also has thermal insulation. Therefore, it is possible to further thermally insulate the cold junction and the pedestal portion.

Next, the manufacturing method of the thermopile type infrared sensor 1 having such a configuration will be described. 3 to 10 are process diagrams showing a method for manufacturing a thermopile infrared sensor.
FIG. 2 shows a release layer forming process for forming the release layer 11.

First, a substrate 10 made of a silicon wafer shown in FIG. Note that the material of the substrate 10 is not limited to silicon, and metal, glass, ceramics, or the like can be used.
FIG. 3B and FIG. 3C are diagrams showing a process of forming the release layer 11 on the substrate 10.
In the step of FIG. 3B, a copper thin film or the like is formed on the substrate 10 as a release layer 11 that can easily peel the infrared sensor from the substrate 10 by a vacuum deposition method.

  Further, in the step of FIG. 3C, a release layer 11 is further formed in the center of the substrate in the same manner as in FIG. 3B on the release layer 11 formed in the step of FIG. To do. Thereby, the peeling layer 11 formed on the board | substrate 10 is comprised by convex shape. By this step, a region where an infrared shielding layer and an insulating layer described later are not formed can be formed.

  As shown in FIG. 4A, a photoresist layer 12 having an opening at a portion where the infrared shielding layer 6 is to be formed is formed of a positive photoresist or the like. Specifically, it is formed on the peeling layer 11 formed on the outer peripheral portion of the peeling layer 11 and the central portion of the substrate 10, that is, on the convex portion of the peeling layer. Thereby, an opening is formed between the release layer 11 or the photoresist layer 12 in the center of the substrate 10 and the outer peripheral portion of the release layer 11.

Next, as shown in FIG. 4B, an infrared shielding layer 6 is formed in the opening by electroplating. In FIG. 4A, since the photoresist layer 12 is formed in the central portion of the substrate 10 and the outer peripheral portion of the release layer 11, the infrared shielding layer 6 is not formed in this portion, and the opening portion Can be formed. In this part, the infrared shielding layer 6 is not formed, and can be formed only in the opening. The infrared shielding layer 6 can also be formed by sputtering, vacuum deposition or the like.
Thereafter, as shown in FIG. 4C, the photoresist layer 12 is removed by etching.
The infrared shielding layer 6 is composed of either an infrared reflecting layer that shields by reflecting infrared rays or an infrared absorbing layer that shields by absorbing infrared rays.

FIG. 5 shows an insulating layer forming step for forming the insulating layer 5.
As shown in FIG. 5, an electrically insulating material, for example, an ultraviolet curable epoxy photoresist is applied by spin coating to form a photoresist layer. Thereafter, exposure and development are performed on the photoresist layer so as to form an outer shape of the sensor in plan view, thereby forming the insulating layer 5. The insulating layer 5 may be made of polyimide or the like. Note that it is possible to make it difficult to transfer heat to the cold junction by using a thermally insulating material such as an ultraviolet curable epoxy photoresist.

  FIG. 6 shows a thermopile forming step of forming a thermopile by forming a thin film pattern made of the first thin film thermocouple material 3 and the second thin film thermocouple material 4.

In the step of FIG. 6A, the first thin film thermocouple material 3 is formed on the insulating layer 5 and the release layer 11 using a vacuum film formation technique such as sputtering to form a first thin film pattern.
Further, unnecessary portions are masked in the step of FIG. 6B, and the second thin film thermocouple material 4 is formed on the first thin film thermocouple material 3, the insulating layer 5, and the release layer as shown in FIG. ) To form a second thin film pattern. After the film formation, the mask is etched, and the first thin film thermocouple material 3 and the second thin film thermocouple material 4, that is, the thermocouple of the first thin film pattern and the second thin film pattern. A cold junction 7 and a warm junction 8 which are contacts are formed. The thermoelectric material of the first thin film thermocouple material 3 and the second thin film thermocouple material 4 can be a combination of various thermoelectric materials such as Ni and Au.

  Furthermore, by forming the output electrode 14 shown in FIG. 2 using the same material as the film-shaped thermocouple, the output electrode 14 can be formed simultaneously with the film-shaped thermocouple forming process. Therefore, when the thermopile infrared sensor is mounted on the wiring board, it is not necessary to separately form an output electrode in order to electrically connect the output electrode 14 and the electrode pad of the wiring board by wire bonding or a conductive material. . Therefore, the mounting area can be reduced, and a small thermopile infrared sensor can be provided.

FIG. 7 shows a film layer forming step for forming the insulating layer (film) 2.
As shown in FIG. 7, an ultraviolet curable epoxy-type photoresist covers the release layer 11, the infrared shielding layer 6, the insulating layer 5, the first thin film thermocouple material 3, and the second thin film thermocouple material 4. In this way, a photoresist layer is formed by applying by spin coating. Note that the film can be formed of a material that is electrically insulating and has a resin as a main component. Thereafter, the photoresist layer is exposed and developed. In this step, of the photoresist layer, the outer peripheral portion of the release layer 11 and the infrared shielding layer 6, that is, the portion constituting the outer peripheral portion of the sensor is removed. Thereby, the remaining photoresist layer forms the film 2. At this time, the thin film thermocouple materials 3 and 4 and the output electrode 14 (FIG. 2) are buried in the insulating film 2. The film 2 may be made of polyimide or the like. Thereby, the infrared shielding layer 6 has the part extended and arrange | positioned from the outer peripheral part of a film.

8 and 9 show a pedestal forming process for radiating the heat from the cold junction 7 of the film thermocouple and forming the pedestal 18 for keeping the temperature of the hot junction 8 constant.
FIG. 8A is a diagram illustrating a process of forming the conductive layer 9 on the film 2. In this step, a conductive layer 9 is formed on the film 2 by sequentially forming a chromium and copper thin film by sputtering or the like.

  FIG. 8B is a diagram illustrating a process of forming a photoresist layer 17 on the conductive layer 9. In this step, a photoresist layer 17 having an opening at a portion that becomes the pedestal 18 is formed on the conductive layer 9 by dry film photoresist. Specifically, the photoresist layer 17 is formed at the edge of the substrate on the conductive layer 9 and at the center of the film 2 on the conductive layer 9. Therefore, the opening is formed from the portion where the cold junction is disposed in the film to the portion where the infrared shielding layer is disposed so as to extend from the outer peripheral portion of the film.

  FIG. 8C is a diagram showing a process of forming a nickel plating layer on the exposed portion on the conductive layer 9. In this step, a nickel plating layer (pedestal portion 18) having a thickness of 30 μm is formed by electroplating using the conductive layer 9.

FIG. 9A is a diagram illustrating a process of removing the photoresist layer 17. After the step of FIG. 8, as shown in FIG. 9A, the photoresist layer 17 is removed by etching.
FIG. 9B is a diagram showing a process of removing a part of the conductive layer 9 and thermally insulating the pedestal 18. As shown in FIG. 9B, using the nickel plating layer (base portion 18) as a masking layer, the nickel plating layer is not formed in the conductive layer 9, that is, the exposed portion is removed by etching. Thereby, the base part 18 thermally insulated is formed. In this step, a sensor main body portion having a plurality of film thermocouples and output electrodes 14 (FIG. 2) and a pedestal portion 18 is formed on the release layer 11 in the film 2.

FIG. 10 shows a process of peeling the sensor body from the interface between the substrate 10 and the release layer 11 and a process of removing the release layer 11 by etching (peeling process).
FIG. 10A is a diagram illustrating a process of removing a part of the release layer 11. As shown in FIG. 10A, the portion of the outer peripheral portion of the substrate where the surface of the release layer is exposed is removed by etching.

FIG. 10B is a diagram illustrating a process of peeling the substrate 10 from the peeling layer 11. As shown in FIG. 10B, the substrate 10 is peeled off at the interface with the release layer 11.
FIG. 10C is a process of removing the release layer 11. As shown in FIG. 10C, the thermopile infrared sensor 1 in which the film-like thermocouple and the output electrode 14 (FIG. 2) are buried in the film 2 is produced by removing the peeling layer 11 by etching.

  The thermopile infrared sensor 1 manufactured as described above has an insulating film 2 in which a light receiving portion in which a hot junction 8 is arranged and a heat radiating portion in which a cold junction 7 is arranged are made of an epoxy resin having a low thermal conductivity. Therefore, a large temperature difference can be created between the cold junction 7 and the hot junction 8. Thereby, an output voltage can be made higher. At the same time, since the film-like thermocouple and the output electrode 14 are buried in the film 2, the surface of the light receiving part of the film 2 becomes a flat surface. Therefore, it is possible to provide the thermopile infrared sensor 1 in which the temperature uniformity of the light receiving portion is increased and a stable output can be given. Furthermore, since heat radiation due to the unevenness of the film 2 can be minimized, the sensitivity can be further improved.

  Further, by forming the pedestal portion 18 with a metal material, the heat radiating portion of the film 2 is supported by the pedestal portion 18 having sufficiently good thermal conductivity with respect to the film 2. As a result, heat is easily radiated from the cold junction 7 of the film-shaped thermocouple that needs to avoid the temperature rise as much as possible through the pedestal portion 18, and the heat radiation effect of the cold junction 7 is enhanced. Thereby, since the temperature rise of the cold junction 7 can be prevented, the temperature difference between the cold junction 7 and the hot junction 8 can be increased, and the electromotive force of the film thermocouple can be increased.

  In addition, an infrared shielding layer 6 is arranged in a region of the film 2 that overlaps the cold junction 7 side of the thermocouple. With this infrared shielding layer 6, heat generated by the infrared shielding layer 6 absorbing a part of infrared rays to be absorbed in the region of the hot junction 8 irradiated from the object to be measured is the infrared shielding layer 6. Heat is efficiently radiated by the pedestal 18 connected by metal. Thereby, the temperature rise of the cold junction 7 by infrared rays can be prevented, and the sensitivity of the thermopile can be further improved.

  Further, the pedestal portion 18 has a structure for radiating the heat of the cold junction 7 and the heat of the infrared shielding layer 6. As a result, the pedestal portion 18 that constitutes the thermopile infrared sensor 1 with a metal covers the outer periphery, so that the thermopile infrared sensor 1 can be reduced in size while ensuring the strength of the thermopile infrared sensor 1 while suppressing the manufacturing cost. . In the present embodiment, the release layer 11 is formed. However, the manufactured infrared sensor may be released from the substrate by forming an infrared shielding layer or the like directly on the substrate without forming the release layer 11.

Next, a first embodiment of the present invention will be described. FIG. 11 shows a cross section of the thermopile infrared sensor module 20 in the second embodiment.
FIG. 11 shows a cross section of the thermopile infrared sensor module 20 in the first embodiment. As shown in FIG. 11, the pedestal 18 of the thermopile infrared sensor 1 is mounted by soldering 21, and the pedestal 18 of the thermopile infrared sensor 1 and the wiring 22 of the wiring board 23 are thermally connected. Thereby, the heat of the base part 18 can be efficiently radiated to the wiring 22 of the wiring board 23. Thereby, it can mount with other components, can simplify a mounting process and can aim at cost reduction.

Next, the thermopile type infrared sensor according to the second embodiment of the present invention will be described.
FIG. 12 shows a cross section of the thermopile infrared sensor 40 in the second embodiment. The detailed description of the same configuration as that of the first embodiment is omitted. In the thermopile type infrared sensor according to the second embodiment, the first embodiment, except that the infrared absorption layer 13 is formed on the portion where the hot junction is formed on the surface of the film on which the pedestal portion 18 is formed. It is the same.

  As shown in FIG. 12, in the thermopile type infrared sensor according to the second embodiment, the infrared absorption layer 13 is formed in the portion where the hot junction is formed on the surface of the film on which the pedestal portion 18 is formed. The infrared absorption layer 13 is a NiCr alloy or gold black formed by sputtering, vacuum deposition, or the like. Infrared rays irradiated from the object to be measured are absorbed by the infrared absorption film 13. Therefore, the temperature of the hot junction 8 side of the thermocouple can be quickly raised by the infrared rays absorbed by the infrared absorption film. Thereby, the sensitivity of a thermopile can further be improved.

1, 40, 100 Thermopile infrared sensor 2 Insulating layer (film)
3, 103 First thermoelectric material 4, 104 Second thermoelectric material 5, 102 Insulating layer 6, 106 Infrared shielding layer 7, 107 Cold junction 8, 108 Hot junction 9 Conductive layer 10, 101 Substrate 11 Peeling layer 12, 17 Photoresist Layers 13, 113 Infrared absorbing layer 14 Output electrode 18 Base (metal)
19 Thermocouple 20 Thermopile Infrared Sensor Module 21 Solder 22 Wiring 23 Wiring Board 105 Protective Film

Claims (20)

A thermopile infrared sensor comprising: a film having electrical insulation; a thermopile disposed on one surface of the film; an infrared shielding layer that covers a part of the film; and a pedestal that supports the film. Because
The film is composed of a resin-based material,
The thermopile is partly or entirely embedded in the film, and is disposed from the center side to the outer peripheral part of the film,
The infrared shielding layer covers the thermopile disposed on the outer peripheral portion of the film on one surface side of the film, and extends from the outer peripheral portion of the film.
The pedestal portion is made of metal, and is disposed from the outer peripheral portion on the other surface side of the film to a portion extending from the outer peripheral portion of the film on the surface side facing the film of the infrared shielding layer. A thermopile infrared sensor characterized by being thermally connected to the film and the infrared shielding layer. The thermopile is composed of a plurality of film-shaped thermocouples joined in series along the surface direction of the film,
The film-shaped thermocouple is composed of two kinds of film-shaped materials joined to each other, and one end side of the film-shaped thermocouple with the first film-shaped material in one film-shaped thermocouple, A hot junction connecting one end side of the second film-like material in one film-like material is arranged on the center side of the film, and the other end of the first film-like material in the one film-like thermocouple A cold junction connecting the side and the other end side of the second film material in the film thermocouple adjacent to the one film thermocouple is disposed on the outer peripheral portion of the film. Item 2. The thermopile infrared sensor according to item 1.   The infrared shielding layer covers the cold junction on one surface side of the film, and the pedestal portion is disposed at a portion where the cold junction is disposed on an outer peripheral portion on the other surface side of the film. The thermopile type infrared sensor according to claim 2. The thermopile infrared sensor according to any one of claims 1 to 3, wherein the pedestal portion is made of a metal deposited by a plating method. The thermopile according to claim 4, wherein a conductive layer is formed on the other surface of the film and a surface of the infrared shielding layer facing the film, and the pedestal is deposited from the conductive layer. Type infrared sensor. The thermopile mold according to claim 5, wherein the pedestal is a material selected from nickel, gold, platinum, rhodium, iron, palladium, copper, or a material mainly composed of a material selected from these materials. Infrared sensor. The thermopile type infrared sensor according to any one of claims 1 to 6, wherein the infrared shielding layer is an infrared reflecting layer. The thermopile infrared sensor according to claim 7, wherein the infrared reflecting layer is made of a metal deposited by a plating method. The thermopile infrared sensor according to any one of claims 1 to 8, wherein the infrared shielding layer is an infrared absorbing layer. The thermopile type infrared sensor according to claim 9, wherein the infrared absorption layer is made of a metal having high infrared absorption such as gold black or NiCr alloy.   The thermopile type infrared sensor according to any one of claims 1 to 10, wherein the infrared shielding layer covers a part of the film via an insulating layer formed on a part of the film. .   The thermopile type infrared sensor according to any one of claims 1 to 11, wherein an infrared absorption layer is formed in a portion where the hot junction on the other surface side of the film is disposed. The thermopile infrared sensor according to any one of claims 1 to 12, wherein the pedestal is thermally bonded to the wiring board by mounting. An infrared shielding layer forming step for forming an infrared shielding layer on the outer peripheral portion of the substrate;
A thermopile forming step of forming a thermopile from the upper part of the central part of the substrate to the upper part of the outer peripheral part;
A film layer forming step of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile;
A pedestal part forming step for forming a pedestal part made of metal from an outer peripheral part of the film to an exposed part of the infrared shielding layer;
A peeling step of peeling the substrate;
A method for manufacturing a thermopile type infrared sensor. A release layer forming step of forming a release layer on the substrate;
An infrared shielding layer forming step of forming an infrared shielding layer on the outer peripheral portion of the release layer; and
A thermopile forming step of forming a thermopile from the upper part of the central part of the substrate to the upper part of the outer peripheral part;
A film layer forming step of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile;
A pedestal part forming step for forming a pedestal part made of metal from an outer peripheral part of the film to an exposed part of the infrared shielding layer;
A peeling step for removing the release layer;
A method for manufacturing a thermopile type infrared sensor. The thermopile forming step includes forming a first thin film pattern made of a first material constituting the film-shaped thermocouple, forming a second material constituting the film-shaped thermocouple, and forming the first thin film pattern A thermopile is formed by forming a second thin film pattern to be joined and forming hot and cold junctions, which are contacts between the first thin film pattern and the second thin film pattern, on the release layer and the insulating layer, respectively. The method of manufacturing a thermopile type infrared sensor according to claim 14 or 15, wherein:   The insulating layer forming step of forming an insulating layer on the center side of the substrate on the infrared shielding layer after the infrared shielding layer forming step and before the thermopile forming step is provided. The manufacturing method of the thermopile type infrared sensor as described in any one of Claims.   In the pedestal portion forming step, a conductive layer having electrical conductivity is formed on the infrared shielding layer and the film, and the pedestal portion is deposited from the conductive layer bonded to the film and the infrared shielding layer. The method for manufacturing a thermopile infrared sensor according to any one of claims 14 to 17, wherein:   In the pedestal portion forming step, after forming the conductive layer, a photoresist layer is formed on a portion of the conductive layer formed at the end of the substrate and a portion of the conductive layer formed at the center of the film. The manufacturing method of the thermopile type infrared sensor of Claim 18 characterized by the above-mentioned. The method for manufacturing a thermopile infrared sensor according to claim 19, wherein the pedestal portion is made of a metal deposited by a plating method.

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