JP5010253B2 - Semiconductor lens, infrared detector using the same, and method for manufacturing semiconductor lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor lens capable of preventing incidence of infrared rays onto a light receiving surface of an infrared detection element through a base part that is a portion other than a lens part, an infrared detector using the lens, and to provide a method of manufacturing the semiconductor lens. <P>SOLUTION: The infrared detector comprises the infrared detection element 1 and a package 2 which stores the infrared detection element 1. The semiconductor lens 3 is arranged from inside of the package 2 so as to cover a rectangular translucent window 23 formed ahead of the light receiving surface of the infrared detection element 1 in the package 2. In the semiconductor lens 3, the perimeter of the base part 3b that is a portion other than the lens part 3a for collecting infrared rays onto the light receiving surface of the infrared detection element 1 is formed in a rectangular shape. The semiconductor lens 3 comprises an infrared block layer 3c which blocks incidence of infrared rays onto the light receiving surface of the infrared detection element 1 through the base part 3b located inside the translucent window 23 by absorption. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor lens, an infrared detector using the same, and a method for manufacturing a semiconductor lens.

  2. Description of the Related Art Conventionally, in the field of light receiving devices and the like, a method for manufacturing a microlens mold using a conductive substrate and a method for manufacturing a microlens using the microlens mold have been proposed (see Patent Document 1). . In Patent Document 1, a synthetic resin lens is exemplified as a microlens.

  In the method for manufacturing a microlens mold disclosed in Patent Document 1, for example, a silicon nitride film is deposited on one surface of a low-resistance p-type silicon substrate that is a conductive substrate, and then a photolithography technique and an etching technique are used. Then, a circular opening is formed at a predetermined portion of the silicon nitride film, and then a part of the one surface side of the p-type silicon substrate is made porous by anodizing using the silicon nitride film as a mask layer. Thus, a hemispherical porous silicon portion is formed. Thereafter, the silicon dioxide portion is formed by oxidizing the entire porous silicon portion, the mask layer is removed, and then the silicon dioxide portion is removed to form a desired convex lens on the one surface of the p-type silicon substrate. A recess corresponding to the shape is formed, and then a thermal oxide film is formed on each of the one surface side and the other surface side of the p-type silicon substrate. In the above-described anodizing treatment, the gap between the cathode disposed opposite to the one surface side of the p-type silicon substrate and the anode plate disposed in contact with the other surface of the semiconductor substrate in the electrolytic solution for anodization. The porous silicon part is formed by energizing the current.

  By the way, in the method for manufacturing a microlens mold disclosed in Patent Document 1, a p-type silicon substrate having a low resistance that is relatively close to the resistivity of a conductor is used. Since the porous silicon substrate isotropically progresses like isotropic etching, the shape of the opening is made circular so that the p-type silicon substrate 90 has the above-mentioned shape as shown in FIG. The depth dimension a1 of the concave portion 91 formed on one surface and the radius a2 of the circular opening surface of the concave portion 91 are substantially equal, and as a result, a spherical lens can be manufactured as a microlens. In addition, Patent Document 1 also discloses that a cylindrical lens can be manufactured as a microlens by making the shape of the opening portion rectangular when manufacturing a microlens mold. Yes.

  However, in the method for manufacturing a microlens mold disclosed in Patent Document 1, only a microlens mold for forming a microlens composed of a convex lens having a uniform curvature radius of a convex curved surface can be manufactured. Therefore, an aspherical lens or a concave lens could not be formed as a microlens. In addition, in the method of manufacturing a microlens mold disclosed in Patent Document 1, the lens diameter (= 2 × a2) of the microlens that can be manufactured is limited by the thickness of the p-type silicon substrate 90, which is larger. In order to manufacture a microlens having a lens diameter, it is necessary to use a p-type silicon substrate 90 having a larger thickness, which increases the cost.

  In addition, it is conceivable to manufacture a plano-concave semiconductor lens by using the method for forming the concave portion 91 in the p-type silicon substrate 90 described in Patent Document 1, but the curvature radius of the concave curved surface is used as the semiconductor lens. However, only a plano-concave spherical lens or cylindrical lens can be formed, and an aspherical lens cannot be formed. Also, in such a method for manufacturing a semiconductor lens, bubbles generated during anodizing treatment are desorbed through the openings of the mask layer, so that bubbles gather around the openings and the rate of progress of porous formation As a result, there is a case where a concave curved surface having a desired radius of curvature cannot be formed.

  Further, conventionally, a method of manufacturing a semiconductor lens made of the remaining portion of the semiconductor substrate by removing a part of the semiconductor substrate has been proposed. The infrared detection element and a can package that houses the infrared detection element are proposed. A can package in which a light transmission window is formed in front of the light receiving surface of the infrared detection element, and an optical element that collects infrared rays on the light reception surface of the infrared detection element disposed from the inside of the can package so as to cover the light transmission window. It has been proposed to use a semiconductor lens as an optical member in an infrared detection device including a member (see, for example, Patent Document 2). Here, in the semiconductor lens manufacturing method described above, the lens portion made of the Fresnel lens is formed using the electron beam lithography technology and the etching technology, and the lens portion and the portion other than the lens portion are formed continuously and integrally. Therefore, for example, a plano-convex lens portion and a flange portion that surrounds the lens portion can be formed continuously and integrally, and it is easy to cover the translucent window from the inside of the can package. It becomes possible to arrange.

Conventionally, an anode without providing a mask layer having a pattern designed in accordance with the mesa shape on one surface side of a semiconductor substrate having a high resistance (for example, a resistivity of about 10 ⁸ Ωcm) such as a semi-insulating GaAs substrate. As a method for forming a mesa shape using an oxidation technique, an anode (electrode) whose shape is designed in accordance with the mesa shape is brought into contact with the other surface side of the semiconductor substrate, and then the above-mentioned semiconductor substrate in the anode and the electrolytic solution. A method has been proposed in which an anodic oxidation process is performed in which an oxide film is formed by energizing a cathode disposed opposite to one surface, followed by an oxide film removal process in which the oxide film is removed by etching (for example, a patent) Reference 3).

In the mesa shape forming method described in Patent Document 3, the in-plane distribution of the current density of the current flowing through the semiconductor substrate is determined by the shape of the anode, the thickness of the oxide film, and the like in the anodic oxidation step. A mesa shape in which the slope is gentle and the side surface and the flat surface of the mesa are smoothly continuous can be formed.
JP 2000-263556 A JP-A-5-133803 Japanese Patent Laid-Open No. 55-13960

  By the way, in the infrared detection device using the semiconductor lens manufactured by applying the technique described in Patent Document 2 or Patent Document 3 as the optical member of the infrared detection device described above, depending on the shape of the lens portion or the light transmission window, In some cases, infrared light that has passed through a portion of the semiconductor lens other than the lens portion located inside the light-transmitting window is incident on the infrared detection element, which decreases the sensitivity of the infrared detection element.

  In the method for manufacturing a semiconductor lens described in Patent Document 2, since the lens portion is formed by etching the semiconductor substrate using the electron beam lithography technique and the etching technique, the aspherical surface having a large curvature radius is used. It was difficult to form a lens.

Then, although it is possible to apply the technique of the said patent document 3 to the manufacturing method of a semiconductor lens, in an anodic oxidation process, with the increase in the thickness of the formed oxide film, it is between an anode and a cathode. For example, when a GaAs substrate having a thickness of 400 μm and a resistivity of 10 ⁸ Ωcm is used as the semiconductor substrate, the thickness of the oxide film is increased when the oxide film is formed with a constant current of 1 mA / cm ^2. Since the potential difference becomes as high as 400 V even if the thickness is about 0.6 μm, it is necessary to repeat the basic process consisting of the anodizing process and the oxide film removing process, which complicates the manufacturing process and provides the desired lens shape. It was difficult to manufacture the semiconductor lens.

  Further, in the technique described in Patent Document 3, since the anode used in the anodizing process is simply pressed against and brought into contact with the other surface of the high-resistance semiconductor substrate, the contact resistance between the semiconductor substrate and the anode is large. The contact between the semiconductor substrate and the anode becomes a Schottky contact, and there is a problem in the controllability and reproducibility of the in-plane distribution of the current density.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a semiconductor lens capable of preventing infrared rays from being incident on the light receiving surface of an infrared detecting element through a base portion which is a portion other than the lens portion. Another object of the present invention is to provide an infrared detector using the same and a method for manufacturing a semiconductor lens.

The invention of claim 1 is disposed from the inside of the package so as to cover a light-transmitting window formed in front of the light receiving surface of the infrared detecting element in the package containing the infrared detecting element, and infrared rays are transmitted to the light receiving surface of the infrared detecting element. A semiconductor lens having a lens portion for condensing light, and an infrared ray blocking layer for blocking infrared rays by absorbing infrared rays is provided on a base portion that is a portion other than the lens portion located inside the translucent window. is a shall, infrared blocking layer is made is formed in the base unit, characterized by comprising the high concentration impurity doped layer which is heavily doped than the lens unit.

According to the present invention, it is possible to block the infrared rays that are to be incident on the infrared detection element through the base portion, which is a part other than the lens portion, by absorbing the infrared rays by the infrared ray blocking layer, and the detection area determined by the shape of the lens portion and the like. It is possible to prevent unnecessary infrared rays from being incident on the infrared detection element, and to increase the sensitivity of the infrared detection element . Moreover, according to this invention, compared with the case where the infrared ray blocking layer is formed of a metal film or an infrared ray absorbing thin film, the heat resistance is increased and the infrared ray absorption characteristics are stabilized. Further, according to the present invention, the infrared blocking layer has high heat resistance and high reliability, and the infrared blocking layer can be formed by doping the base portion with a high concentration of impurities, and the package is made of metal. In the case of being manufactured, electrical contact between the infrared blocking layer and the package is facilitated, and the influence of electromagnetic noise on the infrared detection element can be prevented.

The invention of claim 2 is characterized in that, in the invention of claim 1 , the package is made of metal, and the infrared ray blocking layer also serves as an earth electrode electrically connected to the package.

  According to this invention, the influence of electromagnetic noise on the infrared detection element can be prevented.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a plurality of the lens portions are provided, and the infrared blocking layer is also formed at a boundary portion between the lens portions. And

  According to the present invention, even when a so-called multi-lens is formed in which a plurality of adjacent lens portions are adjacent to each other so as to overlap each other, infrared rays are emitted through a boundary portion between the adjacent lens portions. Can be prevented and high sensitivity can be achieved.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, a multilayer interference filter is formed on at least one surface of the lens portion to transmit infrared light in a desired wavelength region and reflect infrared light in an unnecessary wavelength region. It is characterized by.

  According to the present invention, infrared rays in a desired wavelength region can be transmitted efficiently, while infrared rays in unnecessary wavelength regions can be cut, and high sensitivity of the infrared detection element can be achieved.

According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the lens portion and the base portion are formed of silicon.

  According to the present invention, since the semiconductor lens can be formed using the silicon substrate, the mechanical strength can be increased and the cost can be reduced as compared with the case where the semiconductor lens is formed using the compound semiconductor substrate or the like. Can be planned.

The invention according to claim 6 is an infrared detection element, a package for housing the infrared detection element, a package having a light transmission window formed in front of a light receiving surface of the infrared detection element, and a package so as to cover the light transmission window And an optical member for condensing infrared rays onto the light receiving surface of the infrared detection element, and using the semiconductor lens according to any one of claims 1 to 5. It is characterized by.

  According to the present invention, it is possible to prevent infrared rays from entering the light receiving surface of the infrared detection element through the base portion, which is a portion other than the lens portion of the semiconductor lens, and high sensitivity can be achieved.

Another invention of the present application is arranged from the inside of the package so as to cover a light-transmitting window formed in front of the light receiving surface of the infrared detecting element in the package containing the infrared detecting element, and infrared light is transmitted to the light receiving surface of the infrared detecting element. A semiconductor lens having a lens portion for condensing light, and an infrared ray blocking layer for blocking infrared rays by absorbing infrared rays is provided on a base portion that is a portion other than the lens portion located inside the translucent window. and become one, the infrared blocking layer is made is formed in the base portion, a highly-doped method of manufacturing a semi-conductor lens made of high-concentration impurity-doped layer in comparison with the lens portion, the shape of the lens portion An anode forming step for forming a pattern-designed anode on one surface side of the semiconductor substrate, and a cathode disposed opposite to the other surface side of the semiconductor substrate in the electrolyte and the anode An anodic oxidation process for forming a porous part to be a removal site on the other surface side of the semiconductor substrate and a porous part removing process for removing the porous part. In the anode forming process, the anode and the semiconductor substrate In the anodic oxidation process, a solution for removing oxides of constituent elements of the semiconductor substrate by etching is used as the electrolytic solution in the porous part removing process or in the porous process. The anode is removed after the mass part removing step, and an infrared ray blocking layer forming step for forming an infrared ray blocking layer on the one surface side of the semiconductor substrate after removing the anode is characterized.

According to another inventions of this, since the in-plane distribution of current density of the current flowing through the semiconductor substrate in the anodizing process by the pattern of the anode is formed by anodic formation step is determined, porous forming at anodic oxidation process It is easy to control the in-plane distribution of the thickness of the portion, and in the anode formation step, the anode is formed so that the contact between the anode and the semiconductor substrate becomes an ohmic contact. Since no Schottky barrier occurs, the current flowing during energization in the anodic oxidation process is blocked by the Schottky barrier, the desired current value cannot be obtained, or the instability of the Schottky barrier varies due to instability of the contact resistance. It is possible to prevent the occurrence of malfunctions that occur, and in the anodizing process, as the electrolytic solution, a solution that removes oxides of constituent elements of the semiconductor substrate is used. It is possible to easily form a porous part whose thickness has been continuously changed with a desired thickness distribution by one anodic oxidation process, and by removing the porous part in the porous part removing process. A lens portion having a desired shape can be formed, and the infrared blocking layer is formed after removing the porous portion, so that there are many options for the material of the infrared blocking layer.

A seventh aspect of the present invention is a method of manufacturing a semiconductor lens according to the first aspect, wherein an anode forming step of forming an anode with a pattern designed according to the shape of the lens portion on one surface side of the semiconductor substrate; An anodic oxidation step of forming a porous portion to be a removal site on the other surface side of the semiconductor substrate by energizing between the anode and the cathode opposed to the other surface side of the semiconductor substrate, and the porous portion And removing the porous portion to be removed. In the anode forming step, an anode made of a high-concentration impurity-doped layer is formed in the semiconductor substrate by doping impurities into the semiconductor substrate from the one surface side of the semiconductor substrate. In the anodic oxidation process, a solution for removing oxides of the constituent elements of the semiconductor substrate is used as the electrolytic solution. In the porous part removing process, the high-concentration impurity doping layer is used as an infrared ray. Wherein the selectively removing the porous portion to leave as stop layer.

  According to the present invention, since the in-plane distribution of the current density of the current flowing through the semiconductor substrate in the anodizing process is determined by the anode pattern formed in the anode forming process, the thickness of the porous part formed in the anodizing process is determined. In-plane distribution can be easily controlled, and in the anode forming step, an anode composed of a high-concentration impurity-doped layer is formed in the semiconductor substrate by doping impurities into the semiconductor substrate from the one surface side of the semiconductor substrate. Therefore, no Schottky barrier is formed between the anode and the semiconductor substrate. Therefore, the current flowing during energization in the anodic oxidation process is blocked by the Schottky barrier, a desired current value cannot be obtained, or the Schottky barrier is not broken. It is possible to prevent the occurrence of problems such as in-plane variations in contact resistance due to stability, and in the anodizing process, as an electrolyte, Since a solution that removes the oxides of the constituent elements of the conductor substrate by etching is used, it is possible to easily form a porous part with a desired thickness distribution and continuously changing the thickness in one anodic oxidation process. By selectively removing the porous portion in the porous portion removing step, a lens portion having a desired shape can be formed and the high-concentration impurity-doped layer can be left as an infrared blocking layer. Therefore, the positional accuracy of the infrared blocking layer can be increased.

  According to the first aspect of the present invention, there is an effect that infrared rays can be prevented from entering the light receiving surface of the infrared detecting element through the base portion which is a portion other than the lens portion.

According to the sixth aspect of the present invention, it is possible to prevent infrared rays from entering the light receiving surface of the infrared detecting element through the base portion, which is a portion other than the lens portion of the semiconductor lens, and there is an effect that high sensitivity can be achieved.

According to the seventh aspect of the invention, there is an effect that it is possible to provide a semiconductor lens capable of preventing infrared rays from entering the light receiving surface of the infrared detecting element through the base portion which is a portion other than the lens portion.

(Embodiment 1)
Hereinafter, the infrared detection device of the present embodiment will be described with reference to FIGS.

  The infrared detection device of the present embodiment includes an infrared detection element 1 and a package 2 made of a can package that houses the infrared detection element 1.

  Here, the package 2 includes a disc-shaped stem 21 on which the infrared detection element 1 is mounted, and a metal cap 22 fixed to the stem 21 so as to cover the infrared detection element 1. Two lead terminals 25, 25 connected to the other ends of the bonding wires 24, 24 connected at one end to the respective pads 15 a, 15 c (see FIGS. 3 and 4) penetrate the stem 21. Is provided. The cap 22 is formed in a bottomed cylindrical shape whose rear surface is open, and the rear surface is closed by the stem 21. In addition, a rectangular (in this embodiment, a square shape) translucent window 23 is formed on the front wall of the cap 2 positioned in front of the infrared detection element 1, and infrared rays are transmitted to the light receiving surface of the infrared detection element 1. A semiconductor lens 3 as an optical member for condensing light is disposed from the inside of the cap 22 so as to cover the light transmission window 23.

  As shown in FIGS. 3 and 4, the infrared detection element 1 is formed using a first semiconductor wafer made of a first silicon wafer, and an infrared detection unit 13 that is thermally insulated from the surroundings is formed on one surface side. ing. The outer shape of the infrared detection element 1 is rectangular.

The infrared detector 13 is a thermistor type sensing element whose electric resistance value changes according to temperature, and includes a lower electrode 13a made of a chromium film and a resistor layer 13b made of an amorphous silicon film formed on the lower electrode 13a. And an upper electrode 13c made of a chromium film formed on the resistor layer 13b. Moreover, in the infrared detection element 1 in this embodiment, the infrared absorption layer 17 is laminated | stacked on the infrared detection part 13, and the surface of the infrared absorption layer 17 comprises the light-receiving surface. Here, the infrared detection element 1 assumes infrared of a wavelength band of 8 μm to 13 μm emitted from a human body as infrared to be detected, and adopts SiON as a material of the infrared absorption layer 17. The material of the layer 17 is not limited to SiON, and for example, Si ₃ N ₄ , SiO ₂ , gold black, or the like may be employed. The infrared detector 13 is not limited to a thermistor type sensing element. For example, a thermopile type sensing element, a resistance bolometer type sensing element, a pyroelectric type sensing element, or the like converts a temperature change into an electric signal change. Anything that can be converted is acceptable. In the present embodiment, as is apparent from the above description, the infrared detection element 1 is configured by a thermal infrared detection element. However, the infrared detection element 1 is not limited to a thermal infrared detection element. , InGaAs, InSb, InAs, HgCdTe, PbS, PbSe, or the like may be used, or may be configured by an infrared detecting element using the p-type Ge photon drag effect. Good. Further, the infrared detection element 1 is not limited to one configured by one sensing element, but may be an array type in which a plurality of sensing elements are arranged in an array. The infrared detection device may be a composite type including a plurality of infrared detection elements 1 having different types of sensing elements.

  Incidentally, the infrared detecting element 1 shown in FIGS. 3 and 4 has a recess 10a formed on one surface (upper surface in FIG. 1) of the support substrate 10 formed using the first semiconductor wafer as described above. An infrared detecting section 13 is formed on a thin film base section 11a disposed inside the peripheral section. The base portion 11a is formed in a rectangular shape on the outer periphery, and the support substrate 10 is extended from each of the four corners of the base portion 11a through four beam portions 11b that are continuously and integrally extended along the diagonal direction of the base portion 11a. Is supported by the peripheral portion of the recess 10a. Here, the support substrate 10 has an insulating layer 11 formed on one surface, and each of the beam portions 11b described above is formed continuously and integrally with the insulating layer 11 of the support substrate 10. In short, each beam portion 11b is arranged inside the peripheral portion of the recess 10a in the support substrate 10, and one end portion is continuously connected to the base portion 11a and the other end portion is continuously integrated to the peripheral portion of the recess 10a. It is connected. The insulating layer 11 is formed of a laminated film of a silicon oxide film and a silicon nitride film, but is not limited to the laminated film, and may be formed of, for example, so-called low stress silicon nitride.

  In addition, the infrared detection unit 13 of the infrared detection element 1 is configured such that the lower electrode 13a and the upper electrode 13c are provided on the one surface of the support substrate 10 through metal wirings 14a and 14c extending along different beam portions 11b and 11b. It is electrically connected to the pads 15a and 15c formed on the side. In the present embodiment, the infrared detection unit 13 is thermally insulated from the surroundings using the above-described microbridge structure, but the structure for thermally insulating the infrared detection unit 13 from the surroundings is not limited to the microbridge structure. Alternatively, a heat insulating structure formed of a diaphragm-like film may be used.

  Further, the semiconductor lens 3 is disposed from the inside of the package 2 so as to cover the transparent window 23 formed in front of the light receiving surface of the infrared detection element 1 in the package 2 that houses the infrared detection element 1 as described above. And a lens portion 3a for condensing infrared rays on the light receiving surface of the infrared detection element 1.

  Here, the semiconductor lens 3 is a silicon lens, and as shown in FIG. 1 and FIG. 2, the lens portion 3a is formed in the shape of a plano-convex aspherical lens. The outer peripheral shape of a certain base portion 3b is formed in a rectangular shape.

By the way, the semiconductor lens 3 prevents infrared rays by absorbing infrared rays that are about to enter the light receiving surface of the infrared detection element 1 through the base portion 3b that is a portion other than the lens portion 3a located inside the light transmission window 23. Layer 3c is provided. Here, the infrared blocking layer 3c is composed of a SiO ₂ layer, but the material of the infrared blocking layer 3c is not limited to SiO ₂ , but is Si ₃ N ₄ , SiON, ceramic (for example, Al ₂ O ₃ , Non-metal (insulating material) such as AlN, SiC, etc., low reflectivity metals (conductive material) such as NiCr, graphite, graphite-like carbon, and metal oxides (eg, Ti, Mo, Ni, Al) In the case where the above-described insulating material or metal is used as the infrared blocking layer 3c, the infrared blocking layer 3c has high heat resistance and high reliability. When a metal oxide is used as the material of the infrared ray blocking layer 3c, for example, a metal oxide film may be formed by a sputtering method, a CVD method, or the like, or Ti, Mo, Ni, Al After forming a metal film made of a metal material such as, a metal oxide film may be formed by oxidizing at least a part of the metal film (for example, a part on the surface side of the metal film). .

  Thus, in the semiconductor lens 3 according to the present embodiment, it is possible to block the infrared rays that are to enter the infrared detection element 1 through the base portion 3b, which is a portion other than the lens portion 3a, by the infrared ray blocking layer 3c. It is possible to prevent unnecessary infrared rays from entering the infrared detection element 1 from areas other than the detection area determined by the shape of the infrared detection element 1 and to increase the sensitivity of the infrared detection element 1. In the infrared detection apparatus of the present embodiment, Infrared rays can be prevented from entering the light receiving surface of the infrared detecting element 1 through the base portion 3b which is a portion other than the lens portion 3a of the semiconductor lens 3, and high sensitivity can be achieved. When the metal as described above is used as the material of the infrared blocking layer 3c, the semiconductor lens 3 can be easily in electrical contact with the cap 22, and the semiconductor lens 3 and the cap 22 are electrically connected. Electromagnetic shielding can be performed, and the influence of electromagnetic noise on the infrared detection element 1 can be prevented.

  By the way, in the infrared detection apparatus of this embodiment, although the translucent window 23 of the cap 22 is opened in the rectangular shape, the translucent window 23 of the cap 22 is opened in a circular shape, and the semiconductor lens 3 is attached to the lens unit. It is also conceivable that the cap 22 and the semiconductor lens 3 are bonded together by being configured only by 3a and dropping into the transparent window 23. However, when such a configuration is adopted, when the semiconductor lens 3 is dropped into the light transmitting window 23, the plane perpendicular to the optical axis of the semiconductor lens 3 is inclined with respect to the front wall of the cap 22, and the semiconductor lens 3 and the infrared detection element 1 may not be parallel to each other, and the condensing point of the semiconductor lens 3 may be shifted from the infrared detection element 1.

  On the other hand, in the infrared detection device of the present embodiment, as described above, the opening shape of the translucent window 23 into which the lens portion 3a of the semiconductor lens 3 is dropped in the cap 22 is set to be smaller than the lens diameter of the lens portion 3a. It is a slightly large square shape, and the base portion 3b of the semiconductor lens 3 is in contact with the rear surface of the front wall of the cap 22, and the peripheral portion of the base portion 3b is fixed to the cap 22 via the bonding portion 4 made of an adhesive. It is. Therefore, the parallelism between the semiconductor lens 3 and the infrared detection element 1 can be increased, and the condensing point of the semiconductor lens 3 can be prevented from deviating from the infrared detection element 1.

  Hereinafter, a method for forming the semiconductor lens 3 will be described with reference to FIGS.

First, a cleaning step for cleaning the second semiconductor wafer 30 made of the second silicon wafer shown in FIG. 5A, a mark is provided on one surface (the lower surface in FIG. 5A) of the second silicon wafer 30. After performing the marking process, a metal film having a predetermined film thickness (for example, 1 μm) serving as the basis of the anode 32 (see FIG. 5C) used in the anodizing process on the one surface side of the second semiconductor wafer 30 By performing the conductive layer forming step of forming the conductive layer 31 made of (Al film in this embodiment), the structure shown in FIG. 5B is obtained. Here, in the conductive layer forming step, the conductive layer 31 is formed on the one surface of the second semiconductor wafer 30 by, for example, a sputtering method, and then the conductive layer 31 in an N ₂ gas and H ₂ gas atmosphere. By performing this sintering (heat treatment), the conductive layer 31 in which the contact with the second semiconductor wafer 30 forms an ohmic contact is formed. The method for forming the conductive layer 31 is not limited to the sputtering method, and other known thin film forming methods such as a vapor deposition method may be employed. Further, the material of the conductive layer 31 is not limited to Al, and any material that can make ohmic contact with the second semiconductor wafer 30 may be used. For example, Al—Si containing Al as a main component is used. May be. In the present embodiment, the second semiconductor wafer 30 constitutes a semiconductor substrate.

  After the conductive layer forming step, a patterning step for patterning the conductive layer 31 so as to provide a circular opening 33 in the conductive layer 31 is performed, thereby obtaining the structure shown in FIG. Here, in the patterning step, a resist layer (not shown) in which a portion corresponding to the opening portion 33 is formed on the one surface side of the second semiconductor wafer 30 using a photolithography technique is formed. Thereafter, an unnecessary portion of the conductive layer 31 is removed by etching using, for example, a wet etching technique or a dry etching technique by using the resist layer as a mask, and an opening portion 33 is provided to form an anode 32 composed of the remaining portion of the conductive layer 31. Thereafter, the resist layer is removed. If the conductive layer 31 is an Al film, when unnecessary portions of the conductive layer 31 are removed by wet etching technique, for example, a phosphoric acid-based etchant may be used, and the unnecessary portions of the conductive layer 31 are dried. In the case of etching removal by an etching technique, for example, a reactive ion etching apparatus or the like may be used. Further, in the present embodiment, the conductive layer forming step and the patterning step described above constitute an anode forming step for forming the anode 32 having a pattern designed according to a desired lens shape on the one surface side of the semiconductor substrate. ing.

  After the patterning step, an electric current is passed between the anode 32 and the anode 32 arranged opposite to the other surface side of the second semiconductor wafer 30 (the upper surface side in FIG. 5A) in the electrolytic solution for anodization. The structure shown in FIG. 5D is obtained by performing an anodic oxidation process (anodic oxidation process) for forming a porous portion 34 as a removal site on the other surface side of the second semiconductor wafer 30. In this embodiment, since the second semiconductor wafer 30 has a p-type conductivity, it is necessary to irradiate light on the other surface side of the second semiconductor wafer 30 in the anodic oxidation process. Although there is no need to irradiate light when the second semiconductor wafer 30 is n-type in conductivity type. In addition, as the electrolytic solution, a mixed solution in which a 55 wt% hydrogen fluoride aqueous solution and ethanol are mixed at a ratio of 1: 1 is used. The concentration of the hydrogen fluoride aqueous solution and the mixing ratio of the hydrogen fluoride aqueous solution and ethanol are as follows. There is no particular limitation. Also, the liquid mixed with the aqueous hydrogen fluoride solution is not limited to ethanol, and is not particularly limited as long as it is a liquid that can remove bubbles generated by an anodizing reaction, such as alcohol such as methanol, propanol, and isopropanol (IPA). .

By the way, when a part of the second semiconductor wafer 30 made of the p-type second silicon wafer is made porous in the anodic oxidation step, if the hole is h ⁺ and the electron is e ⁻ , the following reaction occurs. It seems that it is happening.
Si + 2HF + (2-n) h ⁺ → SiF ₂ + 2H ⁺ + ne ⁻
SiF ₂ + 2HF → SiF ₄ + H ₂
SiF ₄ + 2HF → SiH ₂ F ₆
That is, it is known that in the anodic oxidation of the second semiconductor wafer 30 made of the second silicon wafer, porosity or electropolishing occurs due to the balance between the supply amount of F ions and the supply amount of holes h ^+. When the supply amount of F ions is larger than the supply amount of holes, the formation of porosity occurs, and when the supply amount of holes h ⁺ is larger than the supply amount of F ions, electrolytic polishing occurs. Accordingly, when a p-type silicon wafer is used as the second semiconductor wafer 30 as in the present embodiment, the rate of porosity by anodic oxidation is determined by the supply amount of holes h ⁺ . The speed of the porous formation is determined by the current density of the current flowing through the second semiconductor wafer 30, and the thickness of the porous portion 34 is determined. Here, on the other surface side of the second semiconductor wafer 30, 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 33 along the thickness direction of the anode 32 increases. Thus, the porous portion 34 formed on the other surface side of the second semiconductor wafer 30 is gradually thinner as it approaches the center line of the opening portion 33 of the anode 32.

  After the above-described anodic oxidation step is completed, a porous portion removing step for removing the porous portion 34 is performed to obtain the structure shown in FIG. If an alkaline solution (for example, KOH aqueous solution, TMAH aqueous solution, NaOH aqueous solution, etc.) or HF-based solution is used as an etching solution for removing the porous portion 34 in the porous portion removing step, the anode 32 formed of Al. In addition, the anode 32 may be removed after the porous portion removing step.

As described above, after removing the anode 32 during the porous portion removing step or after the porous portion removing step, the infrared blocking layer 3c made of the SiO ₂ film is formed on the one surface side of the second semiconductor wafer 30. Thus, the semiconductor lens 3 having the structure shown in FIG. Note that the infrared blocking layer 3c may be formed using, for example, a thin film formation technique such as a CVD method or a sputtering method, a photolithography technique, and an etching technique.

  Thus, according to the method of manufacturing the semiconductor lens 3 in the present embodiment, the surface of the current density of the current flowing in the second semiconductor wafer 30 as the semiconductor substrate in the anodic oxidation process due to the pattern of the anode 32 formed in the anode forming process. Since the internal distribution is determined, it is possible to control the in-plane distribution of the thickness of the porous portion 34 formed in the anodic oxidation step, and it is possible to form the porous portion 34 whose thickness is continuously changed, In addition, in the anode forming step, since the anode 32 is formed so that the contact between the anode 32 and the second semiconductor wafer 30 is ohmic contact, a Schottky barrier is formed between the anode 32 and the second semiconductor wafer 30. Therefore, the current that flows during energization in the anodizing process is blocked by the Schottky barrier, the desired current value cannot be obtained, or the Schottky barrier is unstable. In addition, it is possible to prevent inconveniences such as in-plane variations in contact resistance. Further, in the anodic oxidation process, a solution for etching away oxides of constituent elements of the second semiconductor wafer 30 is used as the electrolytic solution. Therefore, it is possible to easily form the porous portion 34 whose thickness has been continuously changed with a desired thickness distribution by one anodic oxidation step, and the porous portion 34 can be formed in the porous portion removing step. By removing, the lens portion 3a having a desired shape can be formed, and since the infrared blocking layer 3c is formed after the porous portion 34 is removed, the choice of materials for the infrared blocking layer 3c increases. When a metal oxide is used as the material of the infrared blocking layer 3c, a metal that is a constituent element of the metal oxide is used as the material of the anode 32, and the anode 32 is removed without removing the anode 32. The infrared ray blocking layer 3c made of a metal oxide may be formed by adding an oxidation step for oxidizing the substrate by an oxidation method such as thermal oxidation or anodization.

  By the way, in the manufacturing method of the semiconductor lens 3 described above, the shape of the lens portion 3a (in the present embodiment, the plano-convex non-uniformity) is determined by the in-plane distribution of the current density of the current flowing through the second semiconductor wafer 30 in the anodizing step. Since the aspherical curvature radius and lens diameter of the spherical lens-shaped lens portion 3a are determined, the resistivity and thickness of the second semiconductor wafer 30, the electric resistance value of the electrolyte used in the anodizing step, the second The distance between the semiconductor wafer 30 and the cathode, the planar shape of the cathode (the shape in a plane parallel to the second semiconductor wafer 30 in a state of being opposed to the second semiconductor wafer 30), and the circular shape at the anode 32 By appropriately setting the inner diameter of the opening 33, the shape of the lens portion 3a can be controlled. Here, the electrical resistance value of the electrolytic solution can be adjusted, for example, by changing the concentration of the aqueous hydrogen fluoride solution or the mixing ratio of the aqueous hydrogen fluoride solution and ethanol. By appropriately setting conditions other than the shape of the anode 32 (for example, the electric resistance value of the electrolytic solution), the shape of the lens portion 3a of the semiconductor lens 3 can be more easily controlled. In the manufacturing method of the semiconductor lens 3 described above, the anode 32 provided with the circular opening 33 is formed in the anode forming step. However, the shape of the opening 33 is not circular but rectangular. In this shape, a cylindrical lens can be formed as the semiconductor lens 3. Further, if the anode 32 has a circular planar shape, a plano-concave aspherical lens can be formed as the semiconductor lens 3.

  Further, as shown in FIG. 6, the above-described semiconductor lens 3 transmits an infrared ray in a desired wavelength range (for example, 8 μm to 13 μm) on both surfaces of the lens portion 3 a, and an unnecessary wavelength range (for example, 5 μm or less). A configuration in which multilayer interference filters 3d and 3e that reflect the infrared rays are formed may be employed. In the semiconductor lens 3 having the configuration shown in FIG. 6, multilayer interference filters 3d and 3e that transmit infrared rays in a desired wavelength region and reflect infrared rays in an unnecessary wavelength region are formed on both surfaces of the lens portion 3a. It is possible to cut infrared rays in an unnecessary wavelength range (removing noise caused by sunlight), and high sensitivity can be achieved. In the example shown in FIG. 6, the multilayer interference filters 3d and 3e are formed on both surfaces of the lens portion 3a. However, it may be formed on at least one surface.

(Embodiment 2)
The basic configuration of the infrared detection apparatus of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 7, the semiconductor lens 3 is formed such that the convex curved surface of the lens portion 3 a of the semiconductor lens 3 faces the infrared detection element 1. The point that is attached to the cap 2 is different. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  Thus, in the infrared detection device of the present embodiment, a part of the lens portion 3a of the semiconductor lens 3 does not protrude from the plane including the front surface of the cap 22 through the light transmitting window 23 of the cap 22, and the lens portion 3a Scratches are less likely to improve reliability. Further, in the present embodiment, a metal such as NiCr, graphite, or graphite-like carbon described in the first embodiment is used as the material of the infrared blocking layer 3c, and the infrared blocking layer 3c is electrically connected to the cap 22. It can also serve as an earth electrode, and can more reliably prevent the influence of electromagnetic noise on the infrared detection element 1. The material of the infrared blocking layer 3c is not limited to a metal as described in the first embodiment, and may be a metal oxide or the like. Also in the semiconductor lens 3 of this embodiment, a configuration in which the multilayer interference filters 3d and 3e are formed similarly to the semiconductor lens 3 shown in FIG.

By the way, in the semiconductor lens 3 described in the first and second embodiments, the infrared blocking layer 3c is laminated on the base portion 3b, but the infrared blocking layer 3c has impurities (for example, boron or the like) as shown in FIG. ) May be constituted by a high-concentration impurity doping layer that is highly doped at a concentration of 1 × 10 ¹⁹ cm ⁻³ or more (that is, the infrared blocking layer 3c may be formed in the base portion 3b). Even when the blocking layer 3c is composed of a high-concentration impurity doping layer, the infrared blocking layer 3c can be used as a ground electrode, and has high heat resistance and high reliability. Further, the infrared blocking layer 3c can be formed by doping the base portion 3b with a high concentration of impurities, and metal contamination of the lens portion 3a after the lens portion 3a is formed can be prevented. Further, the infrared blocking layer 3c may be constituted by a porous layer (for example, a porous silicon layer) formed by making a part of the base portion 3b porous.

  Further, in the case where the infrared blocking layer 3c in the semiconductor lens 3 is constituted by a high concentration impurity doping layer, a method for manufacturing the semiconductor lens 3 using the high concentration impurity doping layer as the above-mentioned anode can be considered. Hereinafter, although this manufacturing method is demonstrated based on FIG. 9, description is abbreviate | omitted suitably about the process similar to Embodiment 1. FIG.

First, after performing a cleaning process and a marking process on the second semiconductor wafer 30, a mask layer 36 (for example, a resist layer, a silicon oxide film) patterned for forming the anode 32 on one surface side of the second semiconductor wafer 30 is formed. Etc.) and then an anode forming step of forming an anode 32 made of a high concentration impurity doped layer by doping impurities from the one surface side of the second semiconductor wafer 30. Thus, the structure shown in FIG. In the anode forming step, for example, the low resistance anode 32 made of the high-concentration impurity doping layer may be formed by ion implantation of B ⁺ and thermal diffusion, but the method is not limited to the ion implantation method. May be formed. A low resistance anode 32 is formed. Here, the pattern of the anode 32 is designed according to the shape of the lens portion 3 a, and the opening pattern of the mask layer 36 is designed according to the pattern design of the anode 32.

  After the anode formation step, the structure shown in FIG. 9B is obtained by performing a mask layer removal step for removing the mask layer 36 (in FIG. 9B, the structure of the second semiconductor wafer 30 is described above). It is shown so that one surface side is the lower side).

  After the mask layer removing step, a current introduction electrode (not shown) in contact with the anode 32 is disposed on the one surface side of the second semiconductor wafer 30, and the second semiconductor wafer is contained in the anodic oxidation electrolyte. The other surface side of the second semiconductor wafer 30 is energized through the current introduction electrode between the cathode 32 and the anode 32 arranged opposite to the other surface side of the substrate 30 (the upper surface side in FIG. 9B). The structure shown in FIG. 9C is obtained by performing an anodic oxidation process for forming a porous portion 34 to be a removal site.

  After the end of the anodizing process, a porous part removing process for removing the porous part 34 is performed. Here, if an alkaline solution (for example, KOH aqueous solution, TMAH aqueous solution, NaOH aqueous solution or the like) or HF solution is used as an etching solution for removing the porous portion 34, the porous portion 34 is selected in the porous portion removing step. The semiconductor lens 3 having the structure shown in FIG. 9 (d) provided with the anode 32 made of the above-described high-concentration impurity doping layer as the infrared blocking layer 3 c can be obtained.

  Thus, according to this manufacturing method, in the anode formation step, the second semiconductor wafer 30 is doped by doping impurities into the second semiconductor wafer 30 from the one surface side of the second semiconductor wafer 30 as the semiconductor substrate. Since the anode 32 made of a high-concentration impurity doping layer is formed therein, a Schottky barrier does not occur between the anode 32 and the second semiconductor wafer 30, so that a current that flows during energization in the anodic oxidation process is not generated. It is possible to prevent the occurrence of defects such as interruption of the Schottky barrier, failure to obtain a desired current value, and in-plane variation in contact resistance due to instability of the Schottky barrier. Since a solution for removing the oxide of the constituent element of the second semiconductor wafer 30 by etching is used as the solution, the thickness is continuously increased with a desired thickness distribution. The formed porous portion 34 can be easily formed by one anodic oxidation step, and the lens portion having a desired shape can be obtained by selectively removing the porous portion 34 in the porous portion removing step. 3a can be formed and the high-concentration impurity-doped layer can be left as the infrared blocking layer 3c, so that the positional accuracy of the infrared blocking layer 3c can be increased.

(Working-shaped state 3)
The basic configuration of the infrared detection device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIGS. 10 and 11, the semiconductor lens 3 has a plurality (four) of lens portions 3a and overlaps each other. It is different in that it consists of so-called multi-lenses that are close in shape. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  In the infrared detecting device of the present embodiment, the infrared blocking layer 3c is formed on each of the portion surrounded by the plurality of lens portions 3a and the portion surrounding the plurality of lens portions 3a in the base portion 3b of the semiconductor lens 3. Although the shape of the semiconductor lens 3 is complicated, it is possible to prevent infrared rays from being transmitted through the base portion 3b, which is a portion other than the lens portion 3a of the semiconductor lens 3, and entering the infrared detection element 1.

  In the present embodiment, the semiconductor lens 3 has a plurality of lens portions 3a and the adjacent lens portions 3a are formed to overlap each other, but the plurality of lens portions 3a may be separated from each other. Even in this case, infrared rays can be prevented from being transmitted through the base portion 3b, which is a portion other than each lens portion 3a (including a portion between adjacent lens portions 3a), and incident on the infrared detection element 1. Further, the number of lens portions 3a in one semiconductor lens 3 is not particularly limited.

  By the way, in the semiconductor lens 3 in FIG. 10 and FIG. 11 described above, the adjacent lens portions 3a are formed so as to overlap each other, so that the progress of the infrared rays incident on the boundary portion between the adjacent lens portions 3a. The direction cannot be controlled.

  Therefore, when a multi-lens that is adjacent to each other so that adjacent lens portions 3a overlap each other, as shown in FIG. 12, the infrared blocking layer 3c has a plurality of independent openings for each lens portion 3a. It is desirable that the portion 3f be formed. In the semiconductor lens 3 having the configuration shown in FIG. 12, even if a plurality of lens portions 3a form a multi-lens adjacent to each other such that adjacent lens portions 3a overlap with each other, infrared rays pass through the boundary portion between adjacent lens portions 3a. Can be prevented and high sensitivity can be achieved. Also, in the semiconductor lens 3 of the present embodiment, a configuration in which the multilayer interference filters 3d and 3e are formed similarly to the semiconductor lens 3 shown in FIG. You may comprise by an impurity doping layer and a porous layer.

(Embodiment 4)
The basic configuration of the infrared detection device of the present embodiment is substantially the same as that of the first embodiment, and the semiconductor lens 3 has a biconvex aspherical lens-shaped lens portion 3a as shown in FIG. The only difference is the use of.

  Hereinafter, the manufacturing method of the semiconductor lens 3 in the present embodiment will be described with reference to FIGS. 13A to 13H, but the description of the same steps as those in the first embodiment will be appropriately omitted.

  First, a cleaning process and a marking process are performed on the second semiconductor wafer 30 shown in FIG. 13A, and then the first surface is formed on one surface side of the second semiconductor wafer 30 (the lower surface side in FIG. 13A). First conductivity made of a metal film (Al film in the present embodiment) having a predetermined film thickness (for example, 1 μm) serving as the basis of the first anode 32 (see FIG. 13C) used in the anodizing step. By performing the first conductive layer forming step for forming the layer 31, a structure shown in FIG. 13B is obtained. The first conductive layer 31 is formed so that the contact with the second semiconductor wafer 30 is ohmic contact.

  By performing a first patterning step of patterning the first conductive layer 31 so as to provide a circular opening 33 in the first conductive layer 31 after the first conductive layer forming step, The structure shown in FIG. 13C is obtained. In the first conductive layer forming step and the first patterning step, the first anode 32 that is designed according to the shape of the lens portion is placed on the one surface side of the second silicon wafer 30 that is a semiconductor substrate. A first anode forming step is formed.

  After the first patterning step, the first anode 32 and the cathode disposed opposite to the other surface side of the second semiconductor wafer 30 (upper surface side in FIG. 13A) in the electrolytic solution for anodization. The structure shown in FIG. 13D is performed by conducting a first anodic oxidation step for forming a first porous portion 34 that becomes a removal site on the other surface side of the second semiconductor wafer 30 by energizing the second semiconductor wafer 30. Get.

  After the first anodic oxidation step is completed, a first porous portion removing step for removing the first porous portion 34 is performed. Here, if an alkaline solution (for example, KOH aqueous solution, TMAH aqueous solution, NaOH aqueous solution or the like) or HF-based solution is used as an etching solution for removing the first porous portion 34, in the first porous portion removing step, The first anode 32 formed of Al can also be removed by etching, and the structure shown in FIG. 13E can be obtained. Note that the first porous portion removing step and the first anode removing step of removing the first anode 32 may be performed separately.

  After the first porous portion removal step, the side of the second semiconductor wafer 30 on which a curved surface is formed by removing the first porous portion 34 (that is, the other surface side of the second semiconductor wafer 30). On the opposite side (that is, on the one surface side of the second semiconductor wafer 30), the second anode 42 (designed according to the shape of the desired lens portion 3a in the same manner as in the first anode forming step) Here, the second anode 42 is provided with a circular aperture 33 of the first anode 32 and a circular aperture whose center line along the thickness direction of the second anode 42 coincides. The pattern shown in FIG. 13F is obtained.

  Thereafter, the second porous portion 44 having a thickness distribution corresponding to a desired lens shape is formed on the one surface side of the second semiconductor wafer 30 in the same manner as in the first anodic oxidation step described above. By performing the anodic oxidation step, the structure shown in FIG.

  After the completion of the second anodizing step, a second porous portion removing step for removing the second porous portion 44 is performed, and then the infrared blocking layer 3c is formed on the other surface side of the second semiconductor wafer 30. By performing the infrared blocking layer forming step to be formed, the semiconductor lens 3 having the structure shown in FIG.

  According to the manufacturing method of the semiconductor lens 3 described above, the semiconductor lens 3 having the lens portion 3a in the shape of a biconvex lens and having the infrared ray blocking layer 3c is formed. The semiconductor lens 3 having the lens portion 3a having a shape such as an uneven lens and the infrared blocking layer 3c is manufactured by appropriately changing the pattern design of the first anode 32 and the second anode 42 described above. It is also possible. Also, in the semiconductor lens 3 of the present embodiment, a configuration in which the multilayer interference filters 3d and 3e are formed similarly to the semiconductor lens 3 shown in FIG. You may comprise by an impurity doping layer and a porous layer.

  By the way, in each said embodiment, although the p-type silicon substrate (2nd silicon wafer) is employ | adopted as a semiconductor substrate used as the foundation of the semiconductor lens 3, the material of a semiconductor substrate is not restricted to Si, Ge, SiC Other materials that can be made porous by anodizing treatment, such as GaAs, GaP, InP, etc., may be used, and the conductivity type is not limited to p-type, but may be n-type. However, when the conductivity type of the semiconductor substrate is p-type, the porous portion can be formed without irradiating the semiconductor substrate with light in the anodic oxidation process. Compared to the case, the anodizing apparatus used in the anodizing process can be simplified, and the cost can be reduced.

  As the electrolytic solution used in the anodizing step and removing the oxide of the constituent element of the semiconductor substrate, for example, an electrolytic solution as shown in Table 1 below may be used.

  Note that a metal substrate (for example, an Al substrate, a Ti substrate, or the like) that can be made porous by anodization can be used instead of the semiconductor substrate.

The infrared rays detection apparatus in Embodiment 1 is shown, (a) is a schematic plan view, (b) is a schematic sectional drawing. The semiconductor lens in an infrared detection apparatus same as the above is shown, (a) is a schematic sectional view, (b) is a schematic bottom view. It is a schematic sectional drawing of the infrared detection element in an infrared detection apparatus same as the above. It is a schematic plan view of the infrared detection element in an infrared detection apparatus same as the above. It is principal process sectional drawing for demonstrating the manufacturing method of the semiconductor lens in an infrared detection apparatus same as the above. It is a schematic sectional drawing which shows the other structural example of the semiconductor lens in an infrared detection apparatus same as the above. The infrared rays detection apparatus in Embodiment 2 is shown, (a) is a schematic plan view, (b) is a schematic sectional drawing. It is a schematic sectional drawing which shows the other structural example of the semiconductor lens in an infrared detection apparatus same as the above. Is a major step cross-sectional view for explaining a manufacturing method of another configuration example of a semiconductor lens in the high frequency. Shows the infrared detecting device in Embodiment 3, it is (a) is a schematic plan view, (b) approximate Ryakudan view. The semiconductor lens in an infrared detection apparatus same as the above is shown, (a) is a schematic plan view, and (b) is a schematic bottom view. The other example of a structure of the semiconductor lens in an infrared detection apparatus same as the above is shown, (a) is a schematic plan view, (b) is a schematic bottom view. It is principal process sectional drawing for demonstrating the manufacturing method of another semiconductor lens. It is explanatory drawing of the manufacturing method of the conventional metal mold | die for microlenses.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Infrared detection element 2 Package 3 Semiconductor lens 3a Lens part 3b Base part 3c Infrared blocking layer 23 Translucent window 30 2nd semiconductor wafer (semiconductor substrate)
32 Anode (first anode)
34 Porous part (first porous part)
42 2nd anode 44 2nd porous part

Claims (7)

  A lens unit that is disposed from the inside of the package so as to cover a light transmitting window formed in front of the light receiving surface of the infrared detecting element in the package that houses the infrared detecting element, and that collects infrared rays on the light receiving surface of the infrared detecting element. A semiconductor lens having an infrared ray blocking layer that blocks infrared rays by absorbing infrared rays on a base portion other than the lens portion located inside the light-transmitting window. The layer is formed in a base portion, and is composed of a high concentration impurity doped layer that is more highly doped than the lens portion.   2. The semiconductor lens according to claim 1, wherein the package is made of metal, and the infrared ray blocking layer also serves as an earth electrode that is electrically connected to the package.   3. The semiconductor lens according to claim 1, comprising a plurality of the lens portions, wherein the infrared ray blocking layer is also formed at a boundary portion between the lens portions.   The multilayer interference filter which transmits the infrared rays of a desired wavelength range and reflects the infrared rays of an unnecessary wavelength range is formed on at least one surface of the lens unit. The semiconductor lens according to Item.   The semiconductor lens according to claim 1, wherein the lens portion and the base portion are made of silicon.   An infrared detection element, a package for housing the infrared detection element, a package having a light transmission window formed in front of a light receiving surface of the infrared detection element, and an infrared ray disposed from the inside of the package so as to cover the light transmission window An infrared detection device comprising: an optical member that condenses infrared rays on a light receiving surface of a detection element; and the semiconductor lens according to claim 1 is used as the optical member. . A method according to claim 1 Symbol mounting semiconductor lens, an anode forming step of forming an anode patterned design in accordance with the shape of the lens portion on one surface side of the semiconductor substrate, the other surface of the semiconductor substrate in the electrolyte An anodic oxidation step of forming a porous portion to be a removal site on the other surface side of the semiconductor substrate by energizing between the cathode disposed opposite to the anode and the anode, and removing the porous portion to remove the porous portion and a step, in the anode formation step, so as to the impurity high concentration form forming a positive electrode composed of an impurity-doped layer in the semiconductor substrate by doping from one surface to the semiconductor substrate in the semiconductor substrate, the anodic oxidation in step, as an electrolytic solution, an oxide of the constituent elements of the semiconductor substrate to use a solution to etch away, the more porous portion removed Engineering, leaving the high concentration impurity doped layer as an infrared blocking layer The method of manufacturing a semiconductor lens characterized that you selectively remove the porous portion.

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