JP2015049073A - Infrared sensor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for reducing the cost of an infrared sensor module, or for suppressing generation of a quality problem of an infrared sensor module due to fixing of a lens by an adhesive bond.SOLUTION: An infrared sensor element 3, a lens 11 for condensing an infrared ray outside, and a lens holder 12 for supporting the lens 11 so that the infrared ray passed the lens 11 is condensed on the infrared sensor element 3, are mounted on a mounting substrate 2. The lens 11 and the lens holder 12 are formed in an integrated state.

Description

  The present invention relates to an infrared sensor module that detects the temperature of an object using infrared rays generated by the object.

  In recent electronic devices, infrared temperature sensors are frequently used. For example, in addition to being used for an ear-type thermometer and a human sensor, an air conditioner is also controlled such that the presence of a person is detected by an infrared temperature sensor and the temperature is adjusted aiming at the place where the person is present. In such an infrared temperature sensor, infrared rays irradiated from an object may be collected on a sensor element by a lens, and a temperature increase due to radiant heat may be detected in the sensor element.

  For example, the following is known as an infrared sensor module in which such an infrared temperature sensor is incorporated. This infrared sensor module includes an infrared sensor element that detects infrared rays, a signal processing circuit element that processes the output of the infrared sensor element, and a lens that images external infrared rays on the infrared sensor element. And an optical member opening window provided therein and a case for accommodating an infrared sensor element and a signal processing circuit element. The optical member opening window has a thin portion on the surface side where the optical member is mounted at the peripheral portion, and a concave portion is formed between the peripheral portion of the optical member and the peripheral portion of the optical member opening window. The concave portion constitutes a filling portion filled with an adhesive (see, for example, Patent Document 1).

  In this example, an adhesive is filled in the concave portion formed between the peripheral portion of the optical member opening window, which is an infrared incident window, and the peripheral portion of the optical member. For this reason, even when a mount is formed by mounting an adhesive fillet around the mounting surface of the lens at the periphery of the opening window for the optical member, and mounting the lens by heating and pressing, the adhesive is absorbed by the concave portion. . Thereby, it is suppressed that an adhesive protrudes from a mounting surface and a flow-out occurs.

  However, in the above technique, the lens is bonded and fixed to the metal case with an adhesive, and the case is further bonded and fixed to the substrate with an adhesive. As a result, the manufacturing process of the infrared temperature sensor is complicated and the number of parts is increased, which may hinder the cost reduction of the infrared sensor module. In addition, there is a possibility that the lens may become dirty due to the adhesive at the boundary surface between the lens and the case, or quality problems may occur due to variations in the application of the adhesive.

JP2012-103206A Japanese Patent No. 3580126 JP 2012-181157 A

  The present invention has been made in view of the technical problems as described above, and an object of the present invention is to reduce the cost of the infrared sensor module, or to infrared by fixing the lens with an adhesive. It is an object of the present invention to provide a technology that can suppress the occurrence of a quality problem of a sensor module.

The present invention for solving the above problems includes an infrared sensor element on a mounting substrate, a lens for condensing external infrared light, and the infrared light passing through the lens so that the infrared light is condensed on the infrared sensor element. A lens holder for supporting the lens, and the greatest feature is that the lens and the lens holder are integrally formed.

More specifically, the mounting board,
An infrared sensor element that is disposed on the mounting substrate and detects infrared rays;
A lens disposed at a position facing the infrared sensor element;
A lens holder that is disposed on the mounting substrate and supports the lens so that infrared rays passing through the lens can be condensed on the infrared sensor element;
With
The lens and the lens holder are integrally formed.

  According to this, since the process of bonding and fixing the lens to the lens holder can be omitted in the manufacturing process of the infrared sensor module, the manufacturing process can be simplified, and the number of parts and the part cost can be reduced. Further, it is possible to avoid inconveniences such as lens contamination due to the flow of adhesive and quality variations due to variations in the amount of adhesive applied.

  In the present invention, the lens and the lens holder may be integrally formed by a silicon material semiconductor process.

  Here, since silicon is a material that is transparent to infrared rays, it is possible to efficiently guide infrared rays to the infrared sensor element by forming the lens and the lens holder with silicon. In addition, since silicon is a material with good thermal conductivity, forming the entire lens and lens holder with silicon reduces the temperature detection error of the infrared sensor element due to the temperature inside the lens holder rising. It becomes possible to reduce. Further, by processing the silicon material by a general semiconductor process, the lens and the lens holder can be easily formed integrally. Therefore, the present invention can be realized without increasing the load of the manufacturing process.

  In the present invention, the semiconductor process may be a combination of a photolithography process of a silicon material and an etching process.

  The lens and the lens holder are integrally formed by a photolithography process and an etching process of a silicon material, so that the lens and the lens holder can be manufactured using a process and an apparatus similar to a more general ordinary semiconductor manufacturing process. Can be formed integrally. Therefore, it is possible to realize the present invention more reliably without increasing the load of the manufacturing process.

  Further, in the present invention, the semiconductor process includes providing an anode electrode and a cathode electrode with a silicon material sandwiched according to a lens shape, and energizing between the anode electrode and the cathode electrode in an electrolytic solution, The silicon material may comprise a combination of an anodizing step for forming a porous portion on the cathode electrode side and an oxide etching step for removing the porous portion.

  Also by this, the lens and the lens holder can be integrally formed using the same process and apparatus as the semiconductor manufacturing process. Therefore, the present invention can be realized without increasing the load of the manufacturing process.

In the present invention, the lens holder has a cylindrical shape coaxial with the lens,
The lens may be a single-sided convex lens, and may be combined with the lens holder so as to seal the end surface of the lens holder, and may have a convex surface on the side opposite to the lens holder.

  That is, the lens is a one-side convex lens, and the lens is formed so as to close the end surface of the lens holder having a cylindrical shape coaxial with the lens. The convex surface of the lens is disposed on the side opposite to the lens holder. Then, the convex surface of the lens and the lens holder can be integrally formed by performing photolithography and etching on the Si substrate from both the front and back sides. According to this, a manufacturing process can be simplified more and reduction of parts cost can be promoted. In addition, since the convex surface of the lens and the lens holder are arranged on the opposite side, the operation is facilitated even when processing or coating the lens surface. Here, the cylindrical shape is not limited to a cylindrical shape, and includes a shape in which the outer shape and the inner shape of the tube are different, in addition to a rectangular tube and an elliptical tube.

The present invention further includes a circuit unit that is disposed on the mounting substrate and amplifies an output signal from the infrared sensor element,
The infrared sensor element is disposed on the mounting substrate so as to be surrounded by the lens and the lens holder,
The circuit unit is disposed outside the lens holder on the mounting substrate,
On the mounting substrate, the lens holder and the circuit unit may be integrally resin-molded with the optical surface of the lens opposite to the infrared sensor element exposed to the outside.

  According to this, first, since the circuit unit is arranged outside the lens holder, it is possible to reduce the size of the lens holder itself, and it is possible to reduce the component cost and the time required for manufacturing the component. . As a result, the apparatus cost can be reduced. In addition, since the lens holder and the circuit unit are integrally molded with the resin while the optical surface of the lens opposite to the infrared sensor element is exposed to the outside, the lens and the lens holder need not be fixed on the mounting substrate by bonding or the like. However, it is possible to integrate with the mounting substrate, simplify the manufacturing process, prevent the circuit portion and the infrared sensor element from being damaged by static electricity, and improve the reliability of the infrared sensor module. Moreover, since resin generally does not transmit infrared light, it is possible to more reliably suppress infrared stray light from entering the infrared sensor element by resin molding.

  In the present invention, the mounting board may be provided with a position regulating means for regulating the position of the lens holder on the mounting board. By doing so, it is not necessary to adjust the position of the optical axis of the lens and the center of the infrared sensor element, and it becomes possible to easily install the lens holder on the mounting substrate with a device such as a die bonder. As a result, the manufacturing process can be simplified more reliably and the apparatus cost can be reduced.

  In the present invention, the mounting board may be provided with a pedestal for adjusting the distance between the lens and the infrared sensor element by placing the lens holder.

  Here, when the focal length of the lens is taken into consideration, the lens support position by the lens holder is a position away from the infrared sensor element to some extent. Therefore, the height of the lens holder itself is required to be high to some extent. If it does so, reduction of parts cost may be prevented by the amount of processing of a lens holder increasing.

Therefore, in the present invention, in order to secure the distance between the lens and the infrared sensor element, a pedestal is provided on the mounting substrate. According to this, in addition to the height of the lens holder itself, the distance between the lens and the infrared sensor element can be secured by using the height of the pedestal portion.
Therefore, the height and processing amount of the lens holder can be reduced, and the component cost can be reduced. In this case, the pedestal portion may have a function of position restricting means for restricting the position of the lens holder on the mounting substrate. By doing so, both the positioning of the lens holder and the securing of the lens height can be easily realized.

  In the present invention, the inner wall of the lens holder may be shielded by metal.

  That is, in the present invention, since the lens and the lens holder are integrally formed, the lens holder is a material that transmits infrared rays. Then, the infrared stray light that has passed through the lens holder or the infrared stray light reflected inside the lens or the lens holder enters the infrared sensor element, which may cause measurement errors. Moreover, it is not the structure which can fully shield the electromagnetic waves from the outside. Therefore, in the present invention, the inner wall of the lens holder is shielded with metal. According to this, it can suppress that infrared light injects from parts other than a lens, and becomes an error factor of the detection by an infrared sensor element. In addition, invasion of electric field noise from the outside can be suppressed. Thereby, the detection accuracy by the infrared sensor element can be improved. In addition, as a method of forming a shield, a metal may be vapor-deposited on the inner wall of the lens holder, or a metal film may be attached to the inner wall of the lens holder.

In the present invention, on the mounting substrate, the periphery of the circuit part is molded with a non-conductive resin,
Further, the lens holder and the circuit portion molded with the non-conductive resin may be integrally molded with a conductive resin.

  Here, in order to give the whole infrared sensor module resistance to static electricity, it is desirable to mold the whole with a conductive resin. However, if only the portion directly contacting the ASIC is molded with a conductive resin, the ASIC may be destroyed. Therefore, in the present invention, only the periphery of the circuit portion is molded with a non-conductive resin, and then the entire infrared sensor module is molded with a conductive resin. According to this, the tolerance with respect to the static electricity of the whole infrared sensor module can be improved, preventing the short circuit in a circuit part.

  Note that means for solving the above-described problems can be used in combination as much as possible.

  ADVANTAGE OF THE INVENTION According to this invention, the cost of an infrared sensor module can be reduced or generation | occurrence | production of the quality problem of an infrared sensor module by fixing a lens with an adhesive agent can be suppressed.

It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 1 of this invention. It is a figure which shows the first half part of the manufacturing process of the lens assembly which concerns on Example 1 of this invention. It is a figure which shows the latter half part of the manufacturing process of the lens assembly which concerns on Example 1 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 2 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 3 of this invention. It is a figure which shows schematic structure of the other aspect of the infrared sensor module which concerns on Example 3 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 4 of this invention. It is a figure which shows schematic structure of the other aspect of the infrared sensor module which concerns on Example 4 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 5 of this invention. It is a figure which shows schematic structure of the other aspect in the infrared sensor module which concerns on Example 5 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 6 of this invention. It is a figure which shows schematic structure of the 2nd aspect of the infrared sensor module which concerns on Example 6 of this invention. It is a figure which shows schematic structure of the 3rd aspect of the infrared sensor module which concerns on Example 6 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 7 of this invention. It is a figure which shows schematic structure of the infrared sensor module which concerns on Example 8 of this invention.

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings.

<Example 1>
In FIG. 1, schematic structure of the infrared sensor module 1 in a present Example is shown. Fig.1 (a) is sectional drawing seen from the side surface, FIG.1 (b) is a top view. The infrared sensor module 1 includes a lens assembly 10 including a mounting substrate 2, an infrared sensor chip 3, an ASIC (Application Specific Integrated Circuit) 4, a lens 11 and a lens holder 12. The mounting substrate 2 is a laminated substrate for mounting the infrared sensor chip 3 and the ASIC 4, and has a wiring layer 6 patterned into a predetermined shape. The infrared sensor chip 3 is an element that receives and detects infrared rays by converting a temperature rise caused by infrared radiant heat into a voltage, and corresponds to an infrared sensor element in this embodiment. The ASIC 4 is an integrated circuit designed for the infrared sensor module 1 of the present embodiment, and is electrically connected to the infrared sensor chip 3 by the wiring layer 6. The ASIC 4 corresponds to a circuit unit in this embodiment, and amplifies and outputs a detection signal from the infrared sensor chip 3.

  The infrared sensor chip 3 is covered with a lens assembly 10 including a lens 11 and a lens holder 12. The lens 11 and the lens holder 12 in the lens assembly 10 are integrally formed of silicon. As can be seen from FIG. 1B, the lens assembly 10 has a rectangular cross section in a plan view and a side view, and has a substantially rectangular parallelepiped shape. A lens 11 is disposed on the upper surface of the lens assembly 10 so that the optical axis is perpendicular to the mounting substrate 2.

Further, a chip housing portion 13 which is a cylindrical space having a diameter slightly smaller than the diameter of the lens 11 is formed on the mounting substrate 2 side of the lens 11, and has a circular opening on the mounting substrate 2 side. In other words, a chip housing portion 13 is formed on the substrate side of the lens 11 in the lens assembly 10, and a lens holder 12 is formed by the surrounding portion. In this embodiment, the shape of the chip storage portion 13 is cylindrical, but the shape of the chip storage portion is not limited to this.
For example, it may be a cylinder with a polygonal cross section, or may be a cone or a pyramid.

  The lens assembly 10 is placed on the mounting substrate 2 such that the lower end of the lens holder 12 is in contact with the mounting substrate 2. At that time, the lens assembly 10 is fixed after being positioned so that the optical axis of the lens 11 is at the center of the infrared sensor chip 3 in the plan view shown in FIG. The method of fixing the lens assembly 10 to the mounting substrate 2 is not particularly limited, but may be fixed by adhesion or a resin mold described later.

  In this configuration, infrared rays that have passed through the lens 11 are collected on the infrared sensor chip 3. This enables efficient infrared detection in the infrared sensor module 1. Here, since the lens assembly 10 made of silicon has infrared transparency, the infrared sensor chip 3 detects infrared rays with infrared stray light passing through portions other than the lens 11 and electrostatic noise from the outside. May decrease. Therefore, in this embodiment, the metal film 7 is formed on the cylindrical inner wall of the lens holder 12 by vapor deposition of a metal such as gold to block infrared stray light and electrostatic noise. Note that the configuration for blocking infrared stray light and electrostatic noise is not limited to depositing a metal film. Metal foil may be affixed to the inner wall of the lens holder, and an oxide film may be formed in some cases.

  In the infrared sensor module 1 according to the present embodiment, a lens assembly 10 is integrally formed by a lens 11 and a lens holder 12, and the sensor chip 3 is disposed in a chip storage portion 13 in the lens assembly 10. For this reason, it is possible to greatly reduce the number of assembling steps of the lens assembly and reduce the component cost as compared with a configuration in which a lens is bonded to a conventional metal case. In addition, since there is no process of fixing the lens itself to the case with an adhesive, it is possible to suppress inconveniences such as lens contamination and lens position / posture deviation due to the flow of adhesive, and the reliability of the infrared sensor module Can be improved.

  Next, a specific method for manufacturing the lens assembly 10 will be described. For the production of the lens assembly 10 in this embodiment, photolithography and etching techniques used in normal LSI manufacturing are used. An example of the manufacturing process is shown in FIGS. First, the Si substrate 20 on which the upper Si layer 21 and the lower Si layer 23 are formed with the SiO 2 layer 22 interposed therebetween is prepared. In the Si substrate 20, the upper Si layer 21 is a portion where the lens 11 is formed and has a thickness of about 300 μm. The lower Si layer 23 is a portion where the lens holder 12 is mainly formed and has a thickness of about 400 μm.

  A resist layer 24 is formed on the upper surface of the Si layer 21 on the Si substrate 20 by coating, and a gray mask 25 is disposed on the resist layer 24 side of the Si substrate 20 in this state. The gray mask 25 is a kind of multi-tone mask, in which slits having a resolution lower than that of the exposure machine are formed in a dispersed manner, and intermediate gradation is realized by transmitting a part of the exposure through the slits. . By using a gray mask, it is possible to generate an intermediate exposure portion of an intermediate gradation in addition to an exposed portion and an unexposed portion by one exposure. Subsequently, by performing development processing, a resist (photosensitive agent) having a 3D structure as shown in FIG.

In the present embodiment, a resist layer 24 having a 3D structure corresponding to the lens shape is formed on the upper Si layer 21 as shown in FIG. In this state, in order to transfer the same pattern as the 3D resist layer 24 to the upper Si layer 21, silicon is deeply digged and reactive ion etching (Deep Reactive Ion) is performed using the 3D resist layer 24 as a mask.
It is processed by a dry etching method called Etching (DRIE). Then, the etching progresses so that the etching rate of the resist layer and the silicon material is substantially the same, whereby the shape of the 3D resist layer 24 is transferred to the upper Si layer 21 as shown in FIG. Is done.

  FIG. 3 shows the subsequent manufacturing process. After the shape of the resist layer 24 having the 3D structure is transferred to the upper Si layer 21, as shown in FIG. 3A, a normal portion is formed on a portion where the lens holder 12 is to be formed on the lower side of the lower Si layer 23. A resist is applied. And as shown in FIG.3 (b), it etches with respect to the chip | tip accommodating part 13 by deep digging reactive ion etching (Deep Reactive Ion Etching: DRIE). Here, in this embodiment, since the SiO2 layer 22 is provided in the Si substrate 20, the etching by DRIE stops here. Then, as shown in FIG. 3C, the resist is removed by a rinsing process, and the SiO 2 layer 22 corresponding to the chip storage portion 13 is further removed. Finally, the lens assembly 10 is formed by cutting the Si substrate 20 at a position indicated by a broken line in FIG. In this embodiment, the SiO2 layer 22 is interposed as an etching stopper, but may be omitted by controlling the etching amount and speed.

Subsequently, an assembly procedure of the infrared sensor module 1 will be described. First, the infrared sensor chip 3 and the ASIC 4 are mounted on the mounting substrate 2. The infrared sensor chip 3 and the ASIC 4 can be fixed and bonded to the mounting substrate 2 with a paste. Thereafter, wiring connection (connection between the infrared sensor chip 3 and the ASIC 4 and the wiring layer 6 of the mounting substrate 2) is performed by wire bonding. For such wire bonding between the infrared sensor chip 3 and ASIC 4 and the mounting substrate 2, a normal COB (Chip On Board) mounting technique can be applied. The connection between the infrared sensor chip 3 and the ASIC 4 and the wiring layer 6 of the mounting substrate 2 may be performed by a normal soldering process.

  The lens assembly 10 is positioned on the mounting substrate 2 so that the optical axis of the lens 11 coincides with the center of the infrared sensor chip 3, and then fixed by a method such as adhesion. Thus, the infrared sensor chip 3 is sealed inside a space formed by the chip housing portion 13 of the lens assembly 10 and the mounting substrate 2.

  As described above, in this embodiment, the lens 11 and the lens holder 12 in the infrared sensor module 1 are integrally formed by a normal semiconductor forming process. Therefore, the number of parts and the number of assembly steps can be reduced, and the cost reduction of the apparatus can be promoted. Further, since the process of fixing the lens 11 and the case holder 12 by bonding is eliminated, inconveniences such as the flow of the adhesive and the deviation of the bonding position and posture of the lens can be reduced, and the reliability of the infrared sensor module is improved. It becomes possible to make it.

  In the above embodiment, the case where the lens assembly is formed by a normal semiconductor process including a combination of a photolithography process of silicon material and an etching process has been described. However, the semiconductor process in the present invention is not limited to the above process. Hereinafter, another example of the semiconductor process will be described.

In the semiconductor process described here, a conductive layer made of a metal film (for example, an Al film or an Al—Si film) having a predetermined film thickness (for example, 1 μm) serving as a base of the anode is formed on the lower surface of the Si substrate, for example. Form. This conductive layer may be formed by sputtering or vapor deposition. Then, the conductive layer is heat-treated in an N ₂ gas and H ₂ gas atmosphere so that the contact between the Si substrate and the conductive layer is in ohmic contact.

Then, an anode is formed by forming a circular opening in the conductive layer using a photolithography technique and an etching technique. Then, a porous portion serving as a removal site is formed in a region on the cathode side of the Si substrate by energizing between the anode and the cathode disposed opposite to the upper surface of the Si substrate in the electrolytic solution for anodization. The step of forming the porous portion corresponds to an anodizing step. In this anodic oxidation step, the speed of porous formation is determined by the current density of the current flowing in the Si substrate, and the thickness of the porous portion is determined. Therefore, in the region on the cathode side of the Si substrate, the anode The in-plane distribution of the current density is such that the current density gradually increases as the distance from the center line of the aperture portion increases.

  Therefore, the porous portion is formed so as to gradually become thinner as it approaches the center line of the aperture portion of the anode. Then, it is possible to form a lens shape on the Si substrate by removing the porous portion and the anode with an alkaline solution or an HF solution. The step of removing the porous portion corresponds to an etching step. It is possible to form a lens holder on the same principle as this method.

  According to this semiconductor process, since the lens shape is determined by the in-plane distribution of the current density of the current flowing through the Si substrate, the resistivity and thickness of the Si substrate, the electrical resistance value of the electrolyte, and the relationship between the Si substrate and the cathode The lens shape can be controlled by appropriately setting the distance, the planar shape of the cathode, the shape of the aperture in the anode, and the like. The anode may be formed by a high concentration impurity doping layer obtained by doping impurities into the Si substrate. Moreover, you may make it form a double-sided convex lens by performing said process in multiple times by changing the front and back in a Si substrate.

<Example 2>
Next, a second embodiment of the present invention will be described. In the present embodiment, an example in which the entire infrared sensor module 1 described in the first embodiment is resin-molded will be described. FIG. 4A shows a cross-sectional view of the infrared sensor module 31 resin-molded in this embodiment as viewed from the side. In the infrared sensor module 31, the entire module is integrated by resin molding in a state where the lens assembly 10 is placed on the mounting substrate 2 on which the infrared sensor chip 3 and the ASIC 4 are mounted.

  The mold sealing process in which the entire infrared sensor module 1 is resin-molded is a process in which the infrared sensor chip 3 and the ASIC 4 are hardened using a mold resin in order to protect them from external stress, moisture and contaminants. For example, a transfer mold method may be used, and a thermosetting epoxy resin may be used as the resin. According to this, it is not necessary to individually fix the lens assembly 10 on the mounting substrate 2 by bonding or the like, and the entire components of the infrared sensor module 31 can be integrated by resin molding. As a result, the reliability and handleability of the infrared sensor module 31 can be improved.

  At that time, as shown in FIG. 4B, the ASIC 4 may be first sealed with a non-conductive resin mold 33, and then the whole may be further sealed with a conductive resin mold 34. Then, it is possible to prevent the electrodes of the ASIC 4 from being short-circuited and to prevent the ASIC 4 from being destroyed by static electricity.

<Example 3>
Next, Embodiment 3 of the present invention will be described. In this embodiment, an example in which a structure for positioning a lens assembly is formed on a mounting substrate will be described.

FIG. 5 shows a schematic configuration of the infrared sensor module 51 in the present embodiment. FIG. 5A is a cross-sectional view seen from the side, and FIG. 5B is a plan view. In the present embodiment, the same components as those of the infrared sensor module 1 of the first embodiment shown in FIG. As shown in FIG. 5, the mounting substrate 52 of the present embodiment is provided with four convex portions 52 a which are an example of position restricting means for positioning the lens assembly 10. By placing the lens assembly 10 on the mounting substrate 52 with the four side surfaces of the lens assembly 10 having a rectangular parallelepiped shape abutting or opposed to the inner wall of the four convex portions 52a, the lens is mounted. 11 optical axes are aligned with the center of the infrared sensor chip 3.

  The convex portion 52a may be generated by a built-up method in which an insulating layer is formed in multiple layers on the surface of the mounting substrate 52. In this case, the convex portion 52 a may be formed by covering and solidifying an epoxy resin layer on the mounting substrate 2. Of course, an insulating component may be fixed on the mounting substrate 52 by a method such as adhesion. In some cases, the convex portion 52a may be formed by multilayer formation of a conductor.

  FIG. 6 shows an example in which a convex portion for positioning the lens assembly 10 is provided also on the chip storage portion side of the lens holder 12. In this example, four cylindrical protrusions 62 a are arranged along the inner wall of the lens holder 12 on the mounting substrate 62. In addition, four cylindrical auxiliary convex portions 62 b for preventing the lens assembly 10 from rotating about its axis are provided at four corners on the diagonal line of the lens assembly 10. As described above, according to the present embodiment, it is possible to facilitate positioning when the lens assembly is placed on the mounting substrate, and it is possible to more reliably align the optical axis of the lens. It should be noted that the shape and number of the convex portions described in the present embodiment are merely examples, and it is natural that the convex portions as the position restricting means may have other shapes or numbers. In addition, a concave or hole is formed on the mounting substrate instead of a convex, and the entire lower end of the lens holder or the convex provided on the lower end of the lens holder is inserted into the concave or hole on the mounting substrate. It may be configured to be regulated.

<Example 4>
Next, a fourth embodiment of the present invention will be described. In this embodiment, an example in which a pedestal for increasing the height of the lens assembly is provided on the mounting substrate will be described.

  In FIG. 7, schematic structure of the infrared sensor module 71 in a present Example is shown. FIG. 7A is a sectional view seen from the side, and FIG. 7B is a plan view. In the present embodiment, the same components as those of the infrared sensor module 1 of the first embodiment shown in FIG. As shown in FIG. 7, the mounting substrate 72 of this embodiment is provided with a pedestal 72 a for placing the lower end of the lens holder 77 of the lens assembly 75 over the entire circumference of the lower end of the lens holder 77. It has been. Further, four convex portions 72b for positioning the lens assembly 75 are provided integrally with the pedestal portion 72a.

  By mounting the lens assembly 75 on the pedestal portion 72a, a sufficient distance can be ensured between the lens 76 and the infrared sensor chip 3 without increasing the height of the lens holder 77. . As a result, the thickness of the lower Si layer 23 shown in FIG. 2 can be reduced, and the etching amount in the lens holder forming process can be reduced, so that the component cost can be more reliably reduced. Further, by placing the lens assembly 75 on the mounting substrate 72 so that the four side surfaces of the lens assembly 75 are in contact with or opposed to the inner walls of the four convex portions 72a, the optical axis of the lens 76 is infrared. The center of the sensor chip 3 can be easily matched.

  The pedestal portion 72a and the convex portion 72b may be generated by a built-up method in which an insulating layer is formed in multiple layers on the surface of the mounting substrate 72. In this case, the pedestal portion 72a and the convex portion 72b may be formed by covering and solidifying an epoxy resin layer on the mounting substrate 72. Of course, the insulator component may be fixed on the mounting substrate 72 by bonding or the like. In some cases, the protrusion 72b may be formed by forming a multi-layered conductor.

In FIG. 8, the schematic structure of the infrared sensor module 81 which is another aspect in a present Example is shown. FIG. 8A is a sectional view seen from the side, and FIG. 8B is a plan view. As shown in FIG. 8, a mounting portion 82 a for mounting the lower end of the lens holder 87 of the lens assembly 85 is provided on the mounting substrate 82 of this embodiment over the entire circumference of the lower end portion of the lens holder 87. It has been. In this aspect, the upper end surface of the pedestal portion 82a is formed by a slope whose inner side, that is, the height on the infrared sensor chip 3 side is lower than the outer side.

  On the other hand, the lower end portion of the lens holder 87 of the lens assembly 85 is formed by an inclined surface whose inner side, that is, the lens optical axis side is longer than the outer side. The inclination angles of the pedestal portion 82a and the slope of the lower end portion of the lens holder 87 are substantially the same. That is, by placing the lens assembly 85 so that the inclined surface of the upper end portion of the pedestal portion 82a and the inclined surface of the lower end portion of the lens holder 87 are in contact with each other, the lens assembly 87 is at the lowest position due to its own weight and the lens 86. Is automatically stabilized at a position where the optical axis coincides with the center of the infrared sensor chip 3.

  By mounting the lens assembly 85 on the pedestal portion 82a, a sufficient distance can be secured between the lens 86 and the infrared sensor chip 3 without increasing the height of the lens holder 87. . As a result, the thickness of the lower Si layer 23 shown in FIG. 2 can be reduced, and the etching amount in the lens holder forming process can be reduced, so that the component cost can be more reliably reduced. Further, by placing the lens assembly 85 so that the slope of the upper end portion of the pedestal portion 82a is in contact with the slope of the lower end portion of the lens holder 87, the optical axis of the lens 86 is automatically set to the center of the infrared sensor chip 3. Can be matched.

  Also here, the pedestal portion 82a may be generated by a built-up method in which multiple layers of insulators are formed on the surface of the mounting substrate 82. In this case, the pedestal portion 82a may be formed by covering and solidifying an epoxy resin layer on the mounting substrate 82. Of course, an insulating component may be fixed on the mounting substrate 82 by a method such as adhesion. In some cases, the pedestal portion 82a may be formed by forming multiple layers of conductors.

<Example 5>
Next, a fifth embodiment of the present invention will be described. In this embodiment, an example in which a spacer formed by the same method as the lens assembly is interposed between the mounting substrate and the lens assembly will be described.

  9 and 10 show four modes of the infrared sensor module in the present embodiment. FIG. 9A, FIG. 9B, FIG. 10A, and FIG. 10B are all cross-sectional views seen from the side of the infrared sensor module of each aspect. In the present embodiment, the same components as those of the infrared sensor module 1 of the first embodiment shown in FIG. In the embodiment shown in FIG. 9A, a spacer 97 a is interposed between the lower end of the lens holder 97 of the lens assembly 95 and the mounting substrate 2. The spacer 97a has a cross-sectional view equivalent to that of the lens holder 97 of the lens assembly 95 when viewed from the optical axis direction. The spacer 97a and the lens holder 97 or the spacer 97a and the mounting substrate 2 may be fixed by a method such as adhesion, or may be integrated by a resin mold as described in the second embodiment.

  According to this, it is possible to ensure a sufficient distance between the lens 96 and the infrared sensor chip 3 without increasing the height of the lens holder 97 so much. As a result, the thickness of the lower Si layer 23 shown in FIG. 2 can be reduced, and the etching amount in the lens holder forming process can be reduced, so that the component cost can be more reliably reduced.

Next, in the mode shown in FIG. 9B, a spacer 104 a is interposed between the lower end of the lens holder 104 of the lens assembly 102 and the mounting substrate 2. The spacer 104a has an aperture 104b provided with a hole through which light passes in the center at the upper end of a cylindrical member having a cross-sectional view equivalent to the lens holder 104 when viewed from the optical axis direction. Since the spacer 104a has such an aperture portion 104b, the thermal condensing property of the entire system including the lens assembly 102 and the spacer 104a is improved without substantially affecting the infrared ray condensing characteristics of the lens 103. Is possible.

  If it does so, it will be suppressed that the heat | fever by the infrared light which passed the lens 103 accumulate | stores inside the lens assembly 102 and the spacer 104a, and the detection accuracy fall by the temperature of the infrared sensor chip 3 rising excessively. It becomes possible to suppress. In the embodiment shown in FIG. 9B, the metal film 105 is formed on the inner wall of the side surface of the spacer 104a and the lower surface of the portion other than the hole where light of the aperture portion 104b does not pass. As a result, it is possible to more reliably suppress a decrease in detection accuracy of the infrared sensor chip 3 due to incidence of stray light or electromagnetic waves.

  Next, in the embodiment shown in FIG. 10A, a spacer 109 a is interposed between the lower end of the lens holder 109 of the lens assembly 107 and the mounting substrate 2. The spacer 109a has an optical flat plate portion 109b at the upper end of a cylindrical member having a cross-sectional view equivalent to that of the lens holder 109 when viewed from the optical axis direction. Even if the spacer 109a has such an optical flat plate portion 109b, it is possible to obtain the same effect as that shown in FIG. 9B. In the embodiment shown in FIG. 10A, the metal film 105 is formed on the inner side wall of the spacer 109a and the lower surface of the portion of the optical flat plate portion 109b through which light does not pass. As a result, it is possible to more reliably suppress a decrease in detection accuracy of the infrared sensor chip 3 due to incidence of stray light or electromagnetic waves.

  Further, in the embodiment shown in FIG. 10B, a spacer 117 a is interposed between the lower end of the lens holder 117 of the lens assembly 115 and the mounting substrate 2. The spacer 117 a has a lens 116 b at the upper end of a cylindrical member having a cross-sectional view equivalent to that of the lens holder 117. Since the spacer 117a includes such a lens 116b, it is possible to further enhance the infrared condensing characteristic of the lens 106 and to substantially shorten the focal length. As a result, the total height of the lens assembly 115 and the spacer 117a can be suppressed, and the apparatus can be downsized. Further, since the thickness of the lower Si layer 23 shown in FIG. 2 can be reduced and the etching amount of the lens assembly 115 and the spacer 117a can be reduced, the component cost is reduced, and the manufacturing process is simplified or shortened. It is possible. Further, according to this configuration, the aberration of the lens 116 can be corrected by the lens 116b.

<Example 6>
Next, a sixth embodiment of the present invention will be described. In the present embodiment, an example will be described in which a lens array including a plurality of lenses is included in a lens assembly and signals can be obtained from a plurality of infrared sensor chips.

  In FIG. 11, schematic structure of the infrared sensor module 121 in a present Example is shown. FIG. 11A is a sectional view seen from the lens assembly side, and FIG. 11B is a plan view. In the present embodiment, the same components as those of the infrared sensor module 1 of the first embodiment shown in FIG. As shown in FIG. 11, a lens assembly 125 is installed on the mounting substrate 122 of the present embodiment. This lens assembly 125 has a shape in which three lens assemblies 10 shown in FIG. 1 are connected. ing.

That is, the lens assembly 125 is provided with three lenses 126 and three lens holders 127, and the infrared sensor chip 3 is provided in each of the three chip storage portions 128. It is possible to detect the temperature rise due to the infrared rays incident from. Further, the ASIC 124 in this embodiment can amplify signals from the three infrared sensor chips 3 independently.

  According to the present embodiment, it is possible to measure temperature distributions at a plurality of locations with one infrared sensor module 121. Further, in this embodiment, in the lens assembly manufacturing process described with reference to FIG. 3, after the etching is finished, the lens assembly cutting method is changed, and the lens assembly can be manufactured by cutting out from the Si substrate 20 in a state where three are aligned. Therefore, it is possible to manufacture a lens assembly for an infrared sensor array very easily.

  FIG. 12 shows a schematic configuration of an infrared sensor module 131 as a second mode in the present embodiment. In this example, unlike the embodiment shown in FIG. 11, the ASIC is not mounted and it is assumed that the land portion 133 a of the wiring layer 133 is exposed and distributed. In this aspect, it is left to the user how to amplify and process the output signals from the three infrared sensor elements 3, which enables the use with a high degree of freedom.

  Moreover, in FIG. 13, schematic structure of the infrared sensor module 141 as a 3rd aspect in a present Example is shown. In this example, unlike the embodiment shown in FIG. 11, three ASICs 143 are mounted on the back side of the three infrared sensor elements 3 with respect to the mounting substrate 142. In this embodiment, each ASIC 143 amplifies only the signal of the infrared sensor element 3 on the back side thereof. In this aspect, since the ASIC 143 is disposed on the back side of the infrared sensor element 3 with respect to the mounting substrate 142, although the thickness is increased, the area of the infrared sensor module itself can be reduced and the degree of freedom of the mounting location is increased. be able to.

<Example 7>
Next, a seventh embodiment of the present invention will be described. In this embodiment, an example in which a plurality of infrared sensor chips are arranged in a chip housing portion of one lens assembly, and the lens assembly has a lens array including a plurality of lenses corresponding to each infrared sensor chip. Will be described.

  In FIG. 14, schematic structure of the infrared sensor module 151 as another aspect in a present Example is shown. In this example, three infrared sensor chips 3 a to 3 c are arranged in the chip storage portion 159 of one lens assembly 155. 14A is a cross-sectional view as viewed from the lens assembly side, and FIG. 14B is a plan view. Also in FIG. 14, about the structure equivalent to the infrared sensor module 1 of Example 1 shown in FIG. 1, the description is abbreviate | omitted using the same code | symbol.

  In this example, the lens assembly 155 is formed with lenses 156a to 156c corresponding to the infrared sensor chips 3a to 3b as a lens array. Also in this aspect, it is possible to measure the temperature distribution at a plurality of locations with one infrared sensor module 151. In the present invention, since the lens 156 in the lens assembly 155 is formed by a semiconductor process such as DRIE using a photoresist and etching, the degree of freedom of the lens shape is very high. Accordingly, as shown in FIG. 14, it is possible to easily form the three lenses 156a to 156c in one lens assembly 155.

<Example 8>
Next, an eighth embodiment of the present invention will be described. In the present embodiment, an example in which a lens assembly and an infrared sensor chip are placed on a lead frame and resin molded will be described.

  FIG. 15 shows a schematic configuration of the infrared sensor module 161 in the present embodiment. In this example, the lens assembly 165 and the infrared sensor chip 3 are disposed on a lead frame as a mounting substrate. In this embodiment, the infrared sensor chip 3 is placed on the die pad 164 in the lead frame, and is connected to the leads 162 by wire bonding 163. A lens assembly 165 including a lens 166 and a lens holder 167 is also placed on the lead frame and packaged integrally with a resin mold 168.

  According to the present embodiment, the infrared sensor module 161 including the infrared sensor chip 3 and the lens assembly 165 can be further reduced in size, and the handleability can be improved.

  In the above-described embodiments, the lens is assumed to be a single-sided convex lens, but the lens is not limited to this. A double-sided convex lens or a Fresnel lens may be used. Further, as a material for the lens assembly, germanium or the like may be used in addition to silicon, or a resin such as polyethylene may be used. However, when polyethylene is used, the lens assembly is integrally molded not by a semiconductor manufacturing process such as DRIE but by a resin molding process.

  In the above embodiment, an example in which an infrared sensor chip alone is used as the infrared sensor element has been described. However, for example, an element in which 4 × 4 or 1 × 8 infrared sensor chips are arranged and packaged. May be used.

1, 31, 51, 61, 71, 81, 91, 101, 106, 111, 121, 131, 141, 151, 161 ... infrared sensor module 2, 52, 62, 72, 82, 122, 132, 142 , 152 ... Mounting substrate 3 ... Infrared sensor chip 4, 124, 143, 154 ... ASIC
6 ... conductive layer 7, 105 ... metal shield 10, 75, 85, 95, 102, 107, 115, 125, 155, 165 ... lens assembly 11, 76, 86, 96, 103, 108, 116, 126, 156, 166 ... lenses 12, 77, 87, 97, 104, 109, 117, 127, 157, 167 ... lens holders

Claims (10)

A mounting board;
An infrared sensor element that is disposed on the mounting substrate and detects infrared rays;
A lens disposed at a position facing the infrared sensor element;
A lens holder that is disposed on the mounting substrate and supports the lens so that infrared rays passing through the lens can be condensed on the infrared sensor element;
With
The infrared sensor module, wherein the lens and the lens holder are integrally formed.   The infrared sensor module according to claim 1, wherein the lens and the lens holder are integrally formed by a semiconductor process of a silicon material.   The infrared sensor module according to claim 2, wherein the semiconductor process is a combination of a photolithography process of silicon material and an etching process.   In the semiconductor process, an anode electrode and a cathode electrode are provided with a silicon material sandwiched in accordance with the lens shape, and a current is passed between the anode electrode and the cathode electrode in an electrolytic solution, whereby a cathode electrode side in the silicon material is provided. The infrared sensor module according to claim 2, comprising a combination of an anodizing step for forming a porous portion on the surface and an oxide etching step for removing the porous portion. The lens holder has a cylindrical shape coaxial with the lens,
2. The lens according to claim 1, wherein the lens is a single-sided convex lens, and is coupled to the lens holder so as to seal an end surface of the lens holder, and has a convex surface on the side opposite to the lens holder. The infrared sensor module as described in any one of 1-4. A circuit unit disposed on the mounting substrate and amplifying an output signal from the infrared sensor element;
The infrared sensor element is disposed on the mounting substrate so as to be surrounded by the lens and the lens holder,
The circuit unit is disposed outside the lens holder on the mounting substrate,
6. The lens holder and the circuit unit are integrally molded with a resin on the mounting substrate in a state where an optical surface of the lens opposite to the infrared sensor element is exposed to the outside. The infrared sensor module according to any one of the above.   The infrared sensor module according to claim 1, wherein the mounting substrate is provided with a position restricting unit that restricts a position of the lens holder on the mounting substrate.   The pedestal for adjusting the distance between the lens and the infrared sensor element by placing the lens holder on the mounting substrate is provided. The infrared sensor module according to Item.   The infrared sensor module according to any one of claims 1 to 8, wherein an inner wall of the lens holder is shielded by a metal. On the mounting substrate, mold the periphery of the circuit part with a non-conductive resin,
The infrared sensor module according to claim 6, wherein the lens holder and the circuit part molded with the non-conductive resin are integrally molded with a conductive resin.

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