JP5406082B2 - Thermopile infrared sensor and method for manufacturing the same - Google Patents

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. 14 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-described circumstances, and aims to provide a thermopile type infrared sensor that can reduce the influence of infrared rays at a cold junction in a thermopile and can perform measurement with higher sensitivity and accuracy. .

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 covering a part of the film, and a pedestal that supports the film. A thermopile type infrared sensor, wherein the film is made of a resin-based material, and the thermopile is partly or entirely embedded in the film, along the surface direction of the film. It consists of a plurality of film-shaped thermocouples joined in series, and the film-like thermocouple is made of two kinds of film-like materials joined together, and one of the plurality of film-like thermocouples is one film-like thermocouple A hot junction that connects one end side of the first film-like material to the one end side of the second film-like material of the one film-like material is arranged on the center side of the film, and film A cold junction connecting the other end side of the first film-like material in the thermocouple and the other end side of the second film-like material in the film-like thermocouple adjacent to the one film-like thermocouple is connected to the film The infrared shielding layer covers the cold junction on one surface side of the film via an insulating layer formed on the outer peripheral portion of the one surface of the film, and The pedestal portion extends from the outer peripheral portion, and the pedestal portion is opposed to the first pedestal portion disposed at the portion where the cold junction is disposed on the other surface side of the film, and the film in the infrared shielding layer. A second pedestal portion that is disposed in a portion that extends from the outer peripheral portion on the surface side to be thermally insulated from the first pedestal portion and that is thermally connected to the infrared shielding layer; Consists of And features.

  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. In addition, since the temperature difference between the hot junction of the film-shaped thermocouple that causes a temperature rise 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. . Furthermore, since the infrared sensor is mounted on the wiring board or the like via the pedestal portion, the thermocouple is disposed away from the wiring board or the like. Therefore, the thermal insulation of the thermopile can be ensured. The pedestal portion is divided into a first pedestal portion disposed under the cold junction and an infrared shielding layer, and is divided into a first pedestal portion and a second pedestal portion which is thermally insulated. Thereby, the temperature rise of the cold junction by infrared rays can be prevented, and the sensitivity of the thermopile can be further improved. Moreover, 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.

  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. An electrically conductive layer is formed on the other surface of the film and the surface of the infrared shielding layer facing the film, and the first pedestal is deposited from the conductive layer bonded to the film. The second pedestal portion is deposited from the conductive layer bonded to the infrared shielding portion. 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. And the heat | fever of an infrared shielding layer becomes easy to thermally radiate from a base part. 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. Moreover, when mounting on a board | substrate etc., it can mount by soldering with other components.

  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 that.

  The infrared sensor according to the present invention is characterized in that the first pedestal portion and the second pedestal portion are made of silicon.

  Further, the infrared shielding layer is an infrared reflecting layer. Furthermore, the infrared reflective layer is made of a metal deposited by a plating method. According to this invention, the infrared rays irradiated from the measurement object are reflected by the infrared reflection layer. The heat generated by the partial absorption is dissipated by the connected second pedestal. Thereby, while preventing the temperature rise of the cold junction by infrared rays, the temperature rise of an infrared reflective layer can be suppressed.

  Further, the infrared shielding layer is an infrared absorbing layer. Further, the infrared absorption layer is made of a metal having high infrared absorption such as gold black or NiCr alloy. According to this invention, infrared rays irradiated from the object to be measured are absorbed by the infrared absorption film. The heat generated by absorption is dissipated by the pedestal of the metal to be connected. Thereby, while preventing the temperature rise of the cold junction by infrared rays, the error by the stray light from a peripheral member at the time of mounting, secondary radiation, etc. can be reduced.

  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 infrared sensor according to the present invention is characterized in that the first pedestal portion and the second pedestal portion are thermally bonded to the wiring board by mounting.

  The infrared sensor manufacturing method according to the present invention includes an infrared shielding layer forming step of forming an infrared shielding layer on an outer peripheral portion of a substrate, and an insulating layer forming step of forming an insulating layer on a part of the infrared shielding layer. Forming a first thin film pattern made of a first material constituting a film-shaped thermocouple on the insulating layer and the substrate, comprising a second material constituting the film-shaped thermocouple, Forming a second thin film pattern to be bonded to the first thin film pattern, and forming a hot contact point and a cold contact point as a contact point between the first thin film pattern and the second thin film pattern on the substrate and the insulating layer, respectively. A thermopile forming step of forming a thermopile, a film layer forming step of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile, and the film Forming a first pedestal portion in the portion of the rum where the cold junction is disposed, and forming a second pedestal portion in the exposed portion of the infrared shielding layer; and a peeling step of peeling the substrate. It is characterized by providing.

  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 infrared ray An insulating layer forming step of forming an insulating layer on a central portion side of the peeling layer on the shielding layer; and a first material comprising a first material constituting a film thermocouple on the insulating layer and the peeling layer. The second thin film pattern is formed of the second material constituting the film-shaped thermocouple, the second thin film pattern joined to the first thin film pattern is formed, and the first thin film pattern and the second thin film pattern are formed. A thermopile forming step of forming a thermopile by forming a hot contact and a cold contact as a contact with the thin film pattern on the release layer and the insulating layer, respectively, and electrically insulating so as to cover the thermopile Forming a film having a resin as a main component, forming a first pedestal portion in the portion of the film where the cold junction is disposed, and forming a second portion in the exposed portion of the infrared shielding layer. The base part formation process which forms the base part of this, and the peeling process which removes the said peeling layer are provided, It is characterized by the above-mentioned.

  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 pedestal portion forming step, a conductive layer having electrical conductivity is formed on the infrared shielding layer and the film, and the first pedestal portion is formed. And the second pedestal is deposited from a conductive layer bonded to the film and the infrared shielding layer, respectively.

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

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

  According to the present invention, the temperature of the infrared shielding layer is hardly transmitted to the cold junction side, and the temperature rise of the cold junction can be prevented. Thereby, the influence of the infrared rays of the cold junction in a thermopile can be reduced, and the thermopile type infrared sensor which can measure more accurately and accurately can be provided.

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 thermopile type infrared sensor which concerns on 3rd 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 thermocouple is buried in the film 2, having a pair, a first pedestal portion 15, and a second pedestal portion 16.

  The film 2 is made of a material whose main component is an electrically insulating resin, and has a rectangular shape in plan view when viewed from the thickness direction. As a material of the film 2, for example, an ultraviolet curable epoxy photoresist can be used. The film 2 is supported by the pedestal portion 15 on the outer peripheral side thereof, spans the pedestal portion 1 in the central portion, and constitutes a light receiving portion that receives infrared radiation. That is, the thermopile infrared sensor of this embodiment has a membrane structure in which the outer peripheral portion of the film 2 is supported by the pedestal portion 15.

  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.

  As shown in FIG. 1, the first pedestal portion 15 and the second pedestal portion have a divided structure. Moreover, the 1st base part 15 and the 2nd base part 16 are a rectangular frame type shape which has a through-hole in the center, and the film 2 is formed so that the opening edge of the one side may be covered. Moreover, the 1st base part 15 is arrange | positioned in the part by which the cold junction of a film is arrange | positioned. The 2nd base part 16 is arrange | positioned in the part extended and arrange | positioned from the outer peripheral part in the surface side facing a film in an infrared shielding layer. The second pedestal 16 is thermally connected to the infrared shielding layer. The first pedestal portion 15 and the second pedestal portion 16 are, for example, those in which a plating layer is formed on the conductive layer 9 having electrical conductivity, or those formed of silicon. When the first pedestal portion and the second pedestal portion are formed by plating, the main component is a material selected from nickel, gold, platinum, rhodium, iron, palladium, copper, or a material selected from these materials. Can be made of material. In addition, a conductive layer 9 is formed between the first pedestal 15 and the film 2 and between the second pedestal 16 and the infrared shielding layer 6. The conductive layer 9 is formed on the surface facing the film and the film of the infrared shielding layer.

  In addition, an insulating layer 5 is formed at a portion where the cold junction 7 is disposed on the surface of the thermopile side of the film. 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.

  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. 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 second pedestal portion.

  In FIG. 1, the surface on the thermopile side of the film is formed on the same plane, but depending on the manufacturing method, it may not be formed on the same plane.

  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. 3 shows a release layer forming step for forming the release layer 11.
First, a substrate 10 made of a silicon wafer shown in FIG. 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.

FIG. 4 shows an infrared shielding layer pattern forming process for forming an infrared shielding layer.
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 only be formed. 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 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.

  FIGS. 8 and 9 show a pedestal forming process for forming pedestals 15 and 16 for radiating heat from the cold junction 7 of the film thermocouple and keeping the temperature of the hot junction 8 constant.

  FIG. 8A is a diagram showing a process of forming the electrically 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 openings at portions to be the first pedestal portion 15 and the second pedestal portion 16 is formed on the conductive layer 9 by dry film photoresist. Specifically, the photoresist layer 17 is formed on the end portion of the substrate on the conductive layer 9, the end portion of the film 2 on the conductive layer 9, and the central portion of the film 2 on the conductive layer 9. Therefore, the opening is formed in the part where the cold junction is arranged in the film and the part arranged to extend from the outer peripheral part of the film in the infrared shielding layer.

  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 (first pedestal portion 15 and second pedestal portion 16) having a thickness of 30 μm is formed by electroplating using the conductive layer 9. When the infrared shielding layer 6 has conductivity, the second pedestal 16 can be formed without forming the conductive layer 9 on the infrared shielding layer 6.

  FIG. 9A is a diagram illustrating a process of removing the photoresist layer 17. After the step of FIG. 7, 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 first pedestal portion 15 and the second pedestal portion 16. As shown in FIG. 9B, the nickel plating layer (the first pedestal portion 15 and the second pedestal portion 16) is used as a masking layer and the nickel plating layer is not formed in the conductive layer 9, that is, exposed. The portion that is present is removed by etching. Thereby, the 1st base part 15 and the 2nd base part 16 which were thermally insulated are formed. In this step, a sensor body portion having a plurality of film-like thermocouples and output electrodes 14 (FIG. 2), a first pedestal portion 15 and a second pedestal portion 16 is formed on the release layer 11 in the film 2. Is done.

  FIG. 10 shows a step of peeling the sensor body from the interface between the substrate 10 and the release layer 11 and a release step of removing the release layer 11 by etching.

  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 first pedestal portion 15 with a metal material, the heat radiating portion of the film 2 is supported by the first pedestal portion 15 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 first pedestal portion 15, so that the heat dissipation 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. The second pedestal portion 16 is connected with a metal to efficiently dissipate heat. Further, the pedestal portion is divided into a first pedestal portion 15 disposed under the cold junction and an infrared shielding layer, and is divided into a first pedestal portion 15 and a second pedestal portion 16 that is thermally insulated. . 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. 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.

  FIG. 11 shows a cross section of the thermopile infrared sensor module 20 in the first embodiment. As shown in FIG. 11, the first pedestal 15 and the second pedestal 16 of the thermopile infrared sensor 1 are mounted by soldering 21, and the first pedestal 15 and the second pedestal 15 of the thermopile infrared sensor 1 are mounted. The pedestal portion 16 and the wiring 22 of the wiring board 23 are thermally connected. Thereby, the heat of the 1st base part 15 and the 2nd base part 16 can be thermally radiated to the wiring 22 of the wiring board 23 efficiently. 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. The detailed description of the same configuration as that of the first embodiment is omitted. The thermopile infrared sensor according to the second embodiment is the same as the first embodiment except that the first pedestal part, the second pedestal part, and the conductive layer 9 are different.

  FIG. 12 shows a cross section of the thermopile infrared sensor 30 in the second embodiment of the present invention.

  As shown in FIG. 12, the thermopile infrared sensor 30 of the second embodiment has a thermopile on an insulating base material 25 that is difficult to transfer heat supported by a P-type single crystal Si substrate 24, for example. The thermopile is configured by connecting in series a plurality of thermocouples in which the ends of different metals 3 and 4 are connected as contact points. Various metals can be conceived as the dissimilar metals such as Au and Ni. The insulating base 25 is a thin film containing Si 3 N 4 that can withstand etching of the Si substrate 24. A heat transfer layer 26 is formed along the end face of the insulating substrate 25, and an infrared shielding layer 6 for shielding infrared rays is disposed on the heat transfer layer 26 and the insulating layer 27 on the cold junction 7 side. The heat transfer layer 26 is a metal such as Ni formed by sputtering or the like. The hot contact 8 side of the thermopile is near the center of the insulating base material 25, and the lower Si substrate 24 is etched away in view of heat capacity. The cold junction 7 side in the thermopile is concerned about the inflow of heat to the cold junction, and etches away the Si substrate 24 in the portion along the end of the insulating base material 25 to separate the Si substrate 24 into two. That is, the separated Si substrate 24 corresponds to the first pedestal portion and the second pedestal portion of the first embodiment. Further, the cold junction 7 side of the thermopile is in the vicinity of the periphery of the insulating base material 25, and the lower Si substrate 24 is configured to support the insulating base material 25.

  The thermopile is covered with an insulating layer 27 that transmits infrared rays. An infrared absorption layer 13 that receives infrared rays is disposed on the insulating layer 27 on the warm junction 8 side.

  In the thermopile infrared sensor 30 having the above structure, the first pedestal portion and the second pedestal portion are formed by the Si substrate. Therefore, even if infrared rays from the outside are irradiated to the cold junction 7 side, the cold junction 7 Therefore, the temperature rise of the cold junction 7 is suppressed, and the measurement sensitivity is improved. The thermopile infrared sensor 30 can form the same structure by forming the heat transfer layer 26 and the infrared shielding layer 6 on a sensor element produced by another manufacturing process by a method such as sputtering or vapor deposition. That is, also in this embodiment, an electrically insulating film, a thermopile disposed on one surface side of the film, an infrared shielding layer covering a part of the film, and a pedestal portion that supports the film, In the provided thermopile infrared sensor, the film is made of a resin-based material, and the thermopile is partly or wholly embedded in the film and joined in series along the surface direction of the film. The film thermocouple is composed of two kinds of film materials bonded to each other, and the first film material in one film thermocouple among the plurality of film thermocouples A hot junction connecting one end side of the second film-like material and one end side of the second film-like material in the one film-like material is disposed in the center of the film, and the first film-like material in the one film-like thermocouple The other end of And a cold junction connecting the other end 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, and the infrared shielding layer is formed on one side of the film. On the surface side, the cold junction is covered with an insulating layer formed on the outer peripheral portion of one surface of the film, and is extended from the outer peripheral portion of the film, and the pedestal portion is on the other surface side of the film The first pedestal portion disposed in the portion where the cold junction is disposed and the first pedestal portion and the heat disposed in the portion disposed extending from the outer peripheral portion on the surface facing the film in the infrared shielding layer. And a second pedestal portion thermally insulated from the infrared shielding layer.

Next, the thermopile type infrared sensor according to the third embodiment of the present invention will be described.
FIG. 13 shows a cross section of the thermopile infrared sensor 40 in the third 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 third embodiment, the infrared absorption layer 13 is formed on the surface of the film where the first pedestal 15 is formed, except that the infrared absorption layer 13 is formed on the portion where the hot junction is formed. It is the same as that of one embodiment.

  As shown in FIG. 13, in the thermopile type infrared sensor according to the third embodiment, the infrared absorption layer 13 is formed in the portion where the hot junction is formed on the surface of the film where the first pedestal 15 is formed. ing. 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, 30, 40, 100 Thermopile infrared sensor 2 Film 3, 103 First thermoelectric material 4, 104 Second thermoelectric material 5, 27, 102 Insulating layer 6, 106 Infrared shielding layer 7, 107 Cold junction 8, 108 Hot junction 9 Conductive layer 10, 101 Substrate 11 Release layer 12, 17 Photoresist layer 13, 113 Infrared absorbing layer 14 Output electrode 15, 16 Base (metal)
20 Thermopile Infrared Sensor Module 21 Solder 22 Wiring 23 Wiring Substrate 24 Si Substrate 25 Insulating Base 26 Heat Transfer Layer 105 Protective Film

Claims (15)

A thermopile type comprising an electrically insulating film, a thermopile disposed on one surface of the film, an infrared shielding layer covering a part of the film, and a pedestal for supporting the film. In infrared sensor,
The film is composed of a resin-based material,
The thermopile is composed of a plurality of film-like thermocouples that are partly or wholly embedded in the film and 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 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,
The infrared shielding layer covers the cold junction on one surface side of the film via an insulating layer formed on the outer peripheral portion of the one surface of the film, and extends from the outer peripheral portion of the film. And
The pedestal portion extends from a first pedestal portion disposed at a portion where the cold junction is disposed on the other surface side of the film, and an outer peripheral portion on a surface side facing the film in the infrared shielding layer. And a second pedestal portion that is thermally insulated from the first pedestal portion and thermally connected to the infrared shielding layer. Thermopile type infrared sensor.   2. The thermopile infrared sensor according to claim 1, wherein the first pedestal portion and the second pedestal portion are made of metal deposited by a plating method.   An electrically conductive layer is formed on the other surface of the film and the surface of the infrared shielding layer facing the film, and the first pedestal is deposited from the conductive layer bonded to the film. The thermopile infrared sensor according to claim 2, wherein the second pedestal portion is deposited from the conductive layer bonded to the infrared shielding portion.   The first pedestal part and the second pedestal part are materials selected from nickel, gold, platinum, rhodium, iron, palladium, copper, or a material mainly composed of a material selected from these materials. The thermopile type infrared sensor according to claim 2 or 3.   The thermopile infrared sensor according to any one of claims 1 to 4, wherein the infrared shielding layer is an infrared reflecting layer.   6. The thermopile type infrared sensor according to claim 5, 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 6, wherein the infrared shielding layer is an infrared absorbing layer.   The thermopile infrared sensor according to claim 7, 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 8, wherein an infrared absorption layer is formed in a portion where a hot junction is disposed on the other surface side of the film.   The thermopile infrared sensor according to any one of claims 1 to 9, wherein the first pedestal portion and the second pedestal portion are thermally bonded to a wiring board by mounting. An infrared shielding layer forming step for forming an infrared shielding layer on the outer peripheral portion of the substrate;
An insulating layer forming step of forming an insulating layer on a part of the infrared shielding layer;
On the insulating layer and the substrate, a first thin film pattern made of a first material constituting a film-shaped thermocouple is formed, and made of a second material constituting the film-shaped thermocouple, the first Forming a second thin film pattern to be joined to the thin film pattern, and forming a hot contact point and a cold contact point as a contact point between the first thin film pattern and the second thin film pattern on the substrate and the insulating layer, respectively. A thermopile forming step of forming a thermopile,
A film layer forming step of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile;
Forming a first pedestal portion in the portion of the film where the cold junction is disposed, and forming a second pedestal portion in the exposed portion of the infrared shielding layer; and
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
An insulating layer forming step of forming an insulating layer on the central side of the release layer on the infrared shielding layer;
On the insulating layer and the release layer, a first thin film pattern made of a first material constituting a film-like thermocouple is formed, and made of a second material constituting the film-like thermocouple, Forming a second thin film pattern to be bonded to one thin film pattern, and forming a hot contact point and a cold contact point, which are contacts between the first thin film pattern and the second thin film pattern, on the release layer and the insulating layer, respectively Forming a thermopile to form a thermopile;
A film layer forming step of forming a film mainly composed of an electrically insulating resin so as to cover the thermopile;
Forming a first pedestal portion in the portion of the film where the cold junction is disposed, and forming a second pedestal portion in the exposed portion of the infrared shielding layer; and
A peeling step for removing the release layer;
A method for manufacturing a thermopile type infrared sensor.   In the base portion forming step, a conductive layer having electrical conductivity is formed on the infrared shielding layer and the film, and the first base portion and the second base portion are the film and the The method for manufacturing a thermopile infrared sensor according to claim 11 or 12, wherein the thermopile infrared sensor is deposited from a conductive layer bonded to the infrared shielding layer.   In the pedestal portion forming step, after forming the conductive layer, a portion formed on an end portion of the substrate of the conductive layer, a portion formed on a central portion side of the film of the conductive layer, and the film of the conductive layer The method of manufacturing a thermopile infrared sensor according to claim 13, wherein a photoresist layer is formed on a portion formed at an end of the thermopile type infrared sensor.   The method for manufacturing a thermopile infrared sensor according to claim 14, wherein the first pedestal portion and the second pedestal portion are made of metal deposited by plating.

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