JP2010243365A - Manufacturing method of infrared sensor apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for manufacturing a high-performance infrared sensor apparatus at the high productivity. <P>SOLUTION: The infrared sensor apparatus 30 includes: a package (a base body) 31 for mounting an infrared array sensor (an infrared sensor element) 10 provided with an infrared sensor thin film 2 formed on one surface of a silicon substrate (a substrate) 1, and a cavity 5 formed on the other surface; and a lid (a cover) 33 provided with a lenticular infrared-transparent member 34, and hermetically sealing the infrared array sensor 10. In the manufacturing method of the infrared sensor apparatus 30, after the infrared sensor thin film 2 is formed on one surface of a silicon wafer (a wafer) as a base of the silicon substrate 1, a metal layer 7 is formed on the other surface of the silicon wafer other than at least a cavity formation region in which the cavity 5 is formed. The infrared array sensor 10 is formed, and etched by using the metal layer 7 as a mask. After the infrared array sensor 10 is mounted, it is hermetically sealed by the lid 33 by directly bonding the metal layer 7 of the infrared array sensor 10 and a metal pattern 32 of the package 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an infrared sensor device in which an infrared sensor element mounted on a substrate is surrounded and hermetically sealed by a cover having a lens-shaped infrared transmitting member.

  Conventionally, in order to protect the infrared sensor element and improve the sensor sensitivity of the infrared sensor element, the cover is provided with an infrared transmitting member that transmits infrared light, and the infrared sensor element that is mounted on the base is hermetically sealed. Sensor devices are being researched and developed.

  As this type of infrared sensor device, for example, as shown in FIG. 5, an infrared sensor thin film 2 ′ formed on one surface side of a substrate 1 ′ and an infrared sensor thin film 2 formed on the other surface side of the substrate 1 ′. An infrared sensor element 10 ′ having a cavity 5 for reducing the thickness of the “lower substrate 1”, a stem 41 serving as a base on which the infrared sensor element 10 ′ is mounted on the bottom side, and an infrared transmitting member 34 ′ An infrared sensor device 30 ′ having a cap 43 serving as a cover that hermetically seals the stem 41 around the infrared sensor element 2 ′ mounted on the provided stem 41 has been proposed (see, for example, Patent Document 1). .)

  In this infrared sensor device 30 ′, the infrared sensor element 10 ′ is mounted on the stem 41 via a signal processing chip 37 ′ that cooperates with the infrared sensor element 10 ′. Therefore, the infrared sensor element 10 ′ is bonded to the signal processing chip 37 ′ with the adhesive 7 ′, and the signal processing chip 37 ′ is bonded to the stem 41 with the adhesive 36 ′.

  Further, the infrared sensor element 10 ′ and the signal processing chip 37 ′ are electrically connected by wire bonding with wires 39 and 39. Similarly, the signal processing chip 37 ′ and the external electrodes 35 ′ and 35 ′ as lead pins inserted into the stem 41 are wire-bonded by wires 39 and 39. Here, the infrared sensor device 30 ′ is hermetically sealed using a can package including a cap 43 and a stem 41. Therefore, the infrared transmitting member 34 ′ is sealed so as to cover the opening 43 a of the cap 43. The external electrodes 35 ′ and 35 ′ are sealed with hermetic glasses 40 and 40 in the insertion holes of the external electrodes 35 ′ and 35 ′ in the stem 41.

JP 2006-47085 A

  By the way, in order to improve the performance of such an infrared sensor device 30 ′, infrared rays are incident on the infrared sensor element 10 ′ instead of sealing the stem 41 with a cap 43 provided with an infrared transmitting member 34 ′. It is conceivable to seal a package serving as a base with a lid having a lens-shaped infrared transmitting member to be used as a cover.

  However, when the infrared sensor element 10 ′ is mounted on the bottom surface side of the substrate in the infrared sensor device 30 ′ using an adhesive 7 ′ such as solder or die bond resin, the amount of the adhesive 7 ′ is uniformly distributed on the bottom surface of the substrate. It is difficult to apply to the side. For this reason, even if the vertical position of the infrared sensor element 10 ′ is not inclined with respect to the bottom surface of the base, the relative positional relationship between the lens-shaped infrared transmitting member and the infrared sensor element 10 ′ may be shifted. is there. Further, the adhesive 7 ′ may be softened when the infrared sensor element 10 ′ is bonded to the bottom surface side of the substrate, and the vertical position of the infrared sensor element 10 ′ with respect to the bottom surface of the substrate may change before and after bonding.

  In this case, if the relative positional relationship between the lid having the lens-shaped infrared transmitting member and the infrared sensor element 10 ′ is not accurately aligned, the focal point of the lens-shaped infrared transmitting member is deviated. There exists a problem that the sensor sensitivity of sensor apparatus 30 'falls.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a method of manufacturing an infrared sensor device capable of manufacturing an infrared sensor device having higher sensor sensitivity with high productivity.

  According to a first aspect of the present invention, there is provided an infrared sensor thin film formed on one surface side of a substrate, and a cavity formed on the other surface side of the substrate and spatially separating a part of the infrared sensor thin film from the substrate. An infrared sensor element provided; a base on which the infrared sensor element is mounted; and a lens-shaped infrared transmitting member that allows infrared light to enter the infrared sensor element, and surrounding the infrared sensor element mounted on the base. And a cover for hermetically sealing to the wafer, wherein the infrared sensor thin film is formed on one surface side of the wafer serving as a base of the substrate, and then the other surface side of the wafer A metal layer is formed excluding at least a cavity forming region for forming the cavity, and the cavity forming region is etched from the other surface side of the wafer using the metal layer as a mask. The infrared sensor element is formed on the substrate by bringing the metal layer of the infrared sensor element into contact with and directly bonding the infrared sensor element to the substrate. An infrared sensor element mounting step; and an airtight sealing step for sealing the infrared sensor element mounted on the base body in an airtight manner by the cover.

  According to the present invention, the infrared sensor element is attached to the package by bringing the metal layer of the infrared sensor element used in the formation process of the infrared sensor element into contact with the inner bottom surface of the concave portion of the package and directly bonding the same. By including an infrared sensor element mounting step for mounting, an infrared sensor device with higher sensor sensitivity can be manufactured with high productivity. That is, an infrared sensor device capable of highly accurately aligning the infrared sensor element with the base in the vertical direction can be manufactured.

  According to a second aspect of the present invention, in the first aspect of the invention, in the infrared sensor element mounting step, the metal layer of the infrared sensor element and the metal pattern formed on the base are directly bonded by diffusion bonding. It is characterized by.

  According to the present invention, unlike the case where the infrared sensor element is mounted on the base using the adhesive made of solder or resin, the metal layer of the infrared sensor element can be joined to the metal pattern formed on the base while being solid. Therefore, the position of the infrared sensor element in the vertical direction with respect to the base body does not substantially change before and after joining. Therefore, the infrared sensor element can be mounted with high accuracy on the base in the vertical direction.

  According to a third aspect of the present invention, in the invention of the second aspect, in the infrared sensor element forming step, a through-wiring capable of taking out an output from the infrared sensor thin film in a thickness direction of a wafer serving as a base of the substrate is provided. After penetrating, the metal layer and the through wiring are electrically connected by forming the metal layer, and in the infrared sensor element mounting step, the metal layer and the metal pattern are diffused and bonded. The metal layer and the metal pattern are electrically connected.

  According to the present invention, the metal layer of the infrared sensor element used during the infrared sensor element formation process can be used as an electrode of the infrared sensor element when the infrared sensor element is mounted, and thus further miniaturization is possible. Infrared sensor device can be manufactured with high productivity.

  According to a fourth aspect of the present invention, in the first aspect of the invention, in the infrared sensor element mounting step, the metal layer of the infrared sensor element and the base are directly bonded by anodic bonding. .

  According to the present invention, the metal layer of the infrared sensor element can be directly bonded to the base as it is, unlike the case where the infrared sensor element is mounted on the base using an adhesive made of solder or resin. Therefore, the position of the infrared sensor element in the vertical direction with respect to the base body does not substantially change before and after joining. Therefore, the infrared sensor element can be mounted with high accuracy on the base in the vertical direction.

  According to the first aspect of the present invention, after an infrared sensor thin film is formed on one surface side of a wafer serving as a base of an infrared sensor element substrate, a cavity forming region for forming at least a cavity on the other surface side of the wafer is excluded. Forming an infrared sensor element by etching the cavity forming region from the other surface side of the wafer using the metal layer as a mask, and forming the infrared sensor element from the other surface side of the wafer, and the metal of the infrared sensor element An infrared sensor element mounting step in which the infrared sensor element is mounted on the base body by directly contacting and joining the layer, the metal layer of the infrared sensor element, and the base body, and the cover to the base body. A method of manufacturing an infrared sensor device, comprising: a hermetically sealing step that surrounds the mounted infrared sensor element and hermetically seals the substrate. By an effect that more sensors sensitive infrared sensor device productivity may be produced.

FIG. 3 is a schematic process cross-sectional view illustrating the method for manufacturing the infrared sensor device of the first embodiment. The infrared sensor element is shown, wherein (a) is a schematic plan view, (b) is a schematic plan view of the main part, and (c) is a schematic cross-sectional view corresponding to the A-A ′ cross section of (b). It is a schematic process sectional drawing which shows the manufacturing method of an infrared sensor element same as the above. It is a schematic sectional drawing of the infrared sensor apparatus of Embodiment 2. It is a schematic sectional drawing which shows the conventional infrared sensor apparatus.

(Embodiment 1)
An infrared array sensor will be described with reference to FIG. 2 as an infrared sensor element used in the infrared sensor device of the present embodiment, and a method for manufacturing the infrared array sensor will be described with reference to FIG.

  The infrared array sensor 10 of FIG. 2 is used for an infrared image sensor or the like. FIG. 2A shows m × n (2 × 2 in the illustrated example) thermal infrared detectors 25. They are arranged in a two-dimensional array. The thermal infrared detector 25 as a thermal infrared sensor constituting the infrared array sensor 10 is formed on one surface side of the silicon substrate 1 as a substrate, as shown in the sectional view of FIG. The silicon oxide film 11, the silicon nitride film 12 formed on the silicon oxide film 11, the sensing element 20 formed on the silicon nitride film 12, and the sensing element 20 covered with the surface side of the silicon nitride film 12 The infrared sensor thin film 2 is formed by patterning the laminated structure of the interlayer insulating film 17 formed in the above and the passivation film 19 formed on the interlayer insulating film 17.

  Here, a part of the infrared sensor thin film 2 is spatially separated from the silicon substrate 1 by a cavity 5 formed from the other surface side opposite to the one surface side in the silicon substrate 1. A slit 4 communicating with 5 is provided in the thickness direction of the infrared sensor thin film 2. Further, a metal layer 7 is provided on the other surface of the silicon substrate 1 for bonding the infrared array sensor 10 to a package side serving as a base to be described later. A portion of the infrared sensor thin film 2 that is spatially separated from the silicon substrate 1 constitutes an infrared absorbing portion 21 that absorbs infrared rays.

  The thermal infrared detector 25 is configured by forming the interlayer insulating film 17 with a BPSG (Boro-PhosphoSilicate Glass) film, and forming the passivation film 19 with a PSG (PhosphoSilicate Glass) film and an NSG (Non-doped Silicate Glass) on the PSG film. The laminated film of the interlayer insulating film 17 and the passivation film 19 also serves as the infrared absorption film 22.

  Here, when the refractive index of the infrared absorption film 22 is n and the center wavelength of the infrared ray to be detected is λ, and the thickness t of the infrared absorption film 22 is set to λ / 4n, the wavelength of the detection target (for example, 8 ˜12 μm) infrared absorption efficiency can be increased, and high sensitivity can be achieved. For example, if n = 1.4 and λ = 10 μm, then t≈1.8 μm, the thickness of the interlayer insulating film 17 is 0.8 μm, the thickness of the PSG film is 0.5 μm, and the NSG film The film thickness is 0.5 μm. Note that the passivation film 19 is not limited to the stacked film of the PSG film and the NSG film, and may be formed of, for example, a silicon nitride film.

  As shown in FIG. 2B, the sensing element (temperature sensing part) 20 of the thermal infrared detector 25 includes a p-type polysilicon layer 15 formed over the infrared absorber 21 and the silicon substrate 1, and an n-type polysilicon. A metal material (for example, Al-Si or the like) in which one end of the p-type polysilicon layer 15 and one end of the n-type polysilicon layer 13 are electrically joined to the silicon layer 13 and the infrared incident surface side of the infrared absorption unit 21. The thermopile comprised of the connecting portion 23 is provided.

  Here, the thermopile constituting the sensing element 20 includes the other end of the p-type polysilicon layer 15 and the other end of the n-type polysilicon layer 13 of the thermocouple adjacent to each other on the one surface side of the silicon substrate 1. Are connected in series by wiring 18 made of a metal material (for example, Al—Si).

  In the thermopile constituting the sensing element 20, the one end portion of the n-type polysilicon layer 13, the one end portion of the p-type polysilicon layer 15 and the connection portion 23 form a hot junction on the infrared absorbing portion 21 side. The other end of the silicon layer 15, the other end of the n-type polysilicon layer 13, and the wiring 18 form a cold junction on the silicon substrate 1 side.

  The connection portion 23 formed of a metal material is electrically connected to the n-type polysilicon layer 13 and the p-type polysilicon layer 15 through contact holes 25 formed in the interlayer insulating film 17. . Slits 4 penetrating in the thickness direction of the infrared sensor thin film 2 are formed by etching from the one surface side of the silicon substrate 1 at the four corners of the rectangular region serving as the infrared absorbing portion 21. The slit 4 can thermally separate the thermocouples and improve the sensor sensitivity of the thermal infrared detector 25.

  Further, the cavity 5 can be formed by etching from the other surface side of the silicon substrate 1 using the deep reactive ion etching (hereinafter referred to as “DRIE”) method using the metal layer 7 as an etching mask. The cavity 5 formed on the other surface side of the silicon substrate 1 can cause thermal separation in the infrared sensor thin film 2 and improve the sensor sensitivity of the thermal infrared detector 25.

  Furthermore, in this embodiment, the n-type compensating polysilicon layer 14 and the p-type that are not electrically connected to the infrared incident surface side of the infrared absorbing portion 21 when the n-type polysilicon layer 13 and the p-type polysilicon layer 15 are patterned. The compensation polysilicon layer 16 is left. Such n-type compensating polysilicon layer 14 and p-type compensating polysilicon layer 16 can improve the uniformity of the stress balance of the infrared sensor thin film 2.

  Therefore, the n-type compensating polysilicon layer 14 and the p-type compensating polysilicon layer 16 can prevent warping while reducing the thickness of the infrared sensor thin film 2, and can improve the sensor sensitivity of the thermal infrared detector 25. . The thickness of the laminated infrared sensor thin film 2 is sufficiently smaller than the thickness of the silicon substrate 1. The thickness of the infrared sensor thin film 2 is not limited to the thickness of the infrared sensor thin film 2 constituted by the above-described infrared absorbing film 22 or the like, and may be, for example, about 0.1 μm to 10 μm.

  Hereinafter, the manufacturing method of the infrared sensor element which is the above-mentioned infrared array sensor 10 is demonstrated based on FIG.

  First, the above-described infrared sensor thin film 2 is formed on one surface side of a silicon wafer 3 which is a wafer serving as a base of a silicon substrate 1 which is a substrate. Subsequently, a slit 4 is formed in the thickness direction of the infrared sensor thin film 2 from the one surface side in the silicon wafer 3 so as to form a thermal infrared sensor in the infrared sensor thin film 2 by photolithography technique and etching technique. Next, a resist film 6 is applied and formed on the one surface side of the silicon wafer 3 to protect the infrared sensor thin film 2.

  Subsequently, using Cr as the target material, a Cr film is formed by sputtering on the entire surface of the silicon wafer 3 on the other surface side opposite to the one surface side where the infrared sensor thin film 2 is formed. Subsequently, the target material is changed from the metal Cr to the metal Au, and an Au film is formed on the entire surface of the Cr film formed on the other surface side of the silicon wafer 3 by a sputtering method. As a result, a metal laminated film forming step of forming the metal laminated film 7a composed of the Cr film and the Au film on the Cr film on the entire other surface side of the silicon wafer 3 is performed (FIG. 3A).

  Next, at least the metal laminated film 7a corresponding to the cavity forming region for forming the cavity 5 is removed from the metal laminated film 7a formed on the other surface side of the silicon wafer 3 by photolithography technique and etching technique. Then, a metal layer forming step for forming the metal layer 7 whose outermost surface is made of an Au film is performed. Thus, since the metal layer 7 is collectively formed on the entire surface of the silicon wafer 3, the thickness of the metal layer 7 can be formed uniformly.

  Next, using the formed metal layer 7 as a mask, anisotropic etching is performed from the other surface side of the silicon wafer 3 by the DRIE method, so that the cavity 5 of the infrared array sensor 10 is formed on the other surface side of the silicon wafer 3. An etching process is performed to form a depression that becomes (FIG. 3B).

  Prior to the formation of the metal laminated film 7a, a through-wiring (not shown) penetrating the silicon wafer 3 from the other surface side of the silicon wafer 3 in advance for electrical connection with the infrared sensor thin film 2 in advance. Is forming. Therefore, the metal layer 7 of the infrared array sensor 10 can output the output of the sensing element 20 of the infrared sensor thin film 2 to the metal pattern of the package serving as a base via the through wiring penetrating the silicon substrate 1.

  Thereafter, a temporary fixing sheet sticking step is performed by sticking the temporary fixing sheet 8 through the resist film 6 provided on the one surface side of the silicon wafer 3 (FIG. 3C).

  Here, as the temporary fixing sheet 8, a sheet in which an adhesive is applied on a base material such as plastic or polyester having a thickness of about 1 to 500 μm is suitably used. In view of mass productivity, a heat-peelable pressure-sensitive adhesive sheet is used in which the adhesive strength is reduced by heating in consideration of reducing the adhesive strength in a short time and after processing.

  The heat-peelable pressure-sensitive adhesive sheet is a pressure-sensitive adhesive containing thermally expandable fine particles (for example, rubber pressure-sensitive adhesive, acrylic pressure-sensitive adhesive, vinyl alkyl ether pressure-sensitive adhesive, silicone pressure-sensitive adhesive, polyester pressure-sensitive adhesive, polyamide-based pressure sensitive adhesive). A pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a fluorine-based pressure-sensitive adhesive, or the like) can be used as a pressure-sensitive adhesive layer and formed on a substrate such as polyester. Examples of the thermally expandable fine particles include microcapsules in which a substance that easily expands by gasification by heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell.

  Subsequently, the dicing sheet 9 is attached to the other surface side of the silicon wafer 3, and then the dicing sheet 9 together with the temporary fixing sheet 8 and the resist film 6 is formed along the dicing line 8 a from the one surface side of the silicon wafer 3. The silicon wafer 3 is diced by a dicer so as not to cut all of them. As a result, the plurality of infrared array sensors 10 having the temporarily fixed sheet 8 and the resist film 6 separated on the dicing sheet 9 can be cut from the silicon wafer 3 (FIG. 3D).

  Next, by performing heat treatment or the like on the silicon wafer 3, the temporarily fixed sheet 8 cut into a plurality by the dicer can be removed from the infrared sensor thin film 2 side of each infrared array sensor 10. Here, the temporary fixing sheet 8 made of the heat-peelable pressure-sensitive adhesive sheet is used to heat the individually fixed temporary fixing sheet 8 with a hot air dryer, a hot plate, a near infrared lamp or the like without damaging the infrared sensor thin film 2. It can be peeled from the infrared array sensor 10. That is, the heat-expandable fine particles contained in the pressure-sensitive adhesive of the heat-peelable pressure-sensitive adhesive sheet are greatly expanded by heating. As a result, minute irregularities are formed on the surface of the pressure-sensitive adhesive layer, and the temporary fixing sheet 8 and the infrared sensor thin film 2 of the infrared array sensor 10 are changed from a relatively strong bond to a point bond. Therefore, the adhesion area of the temporary fixing sheet 8 can be reduced and the adhesive force can be greatly reduced.

  After the temporary fixing sheet 8 is peeled off, the resist film 6 formed on the one surface of each infrared array sensor 10 from which the temporary fixing sheet 8 has been peeled is removed by ashing. Specifically, the resist film 6 can be removed using ozone generated by irradiating oxygen gas with ultraviolet rays or high-frequency microwaves. Thus, not only the resist film 6 formed on the one surface side of the infrared array sensor 10 is removed, but also the cavity 5 formed in the slit 4 or the silicon substrate 1 on the one surface side of the infrared array sensor 10. It is also possible to remove unnecessary organic substances adhering to the surface by decomposition surface desorption.

  The infrared array sensor 10 has no damage to the infrared sensor thin film 2, and the infrared array sensor 10 having the metal layer 7 on the other surface side facing the infrared sensor thin film 2 on the silicon substrate 1 is manufactured with high productivity. (FIG. 3 (e)).

  By individually picking up the manufactured infrared array sensor 10 from the dicing sheet 9, each infrared array sensor 10 can be arranged in a package which is a base to be described later.

  Next, the structure of the infrared sensor device in which the infrared array sensor 10 having the metal layer 7 of the present embodiment is mounted on a package as a base will be described, and the manufacturing process will be described with reference to FIG.

  As shown in FIG. 1C, the infrared sensor device 30 houses the infrared array sensor 10 and the signal processing chip 37 that cooperates with the infrared array sensor 10 on the inner bottom surface 31a side of the recess of the package 31. Yes. The metal layer 7 formed on the other surface side facing the one surface on which the infrared sensor thin film 2 is formed on the silicon substrate 1 of the infrared array sensor 10 is a metal provided on the inner bottom surface 31 a of the recess of the package 31. The pattern 32 is directly joined and electrically connected. The signal processing chip 37 cooperating with the infrared array sensor 10 is mounted via metal patterns 38 and 38 and metal bumps (for example, solder bumps) 36 and 36 provided on the inner bottom surface 31a of the recess of the package 31. Electrically connected.

  The infrared array sensor 10 and the signal processing chip 37 are electrically connected through a metal pattern 32 and a metal pattern 38, respectively, and a through electrode (not shown) in which the metal patterns 38 and 38 are provided through the package 31 is illustrated. Are electrically connected to the external electrodes 35 and 35 provided outside the package 31. Further, the inside of the concave portion of the package 31 on which the infrared array sensor 10 and the signal processing chip 37 are mounted is hermetically sealed by a lid 33 which is a cover including an infrared transmitting member 34 having a convex lens shape.

  Hereinafter, each configuration of the infrared sensor device 30 used in the present embodiment will be described in detail.

  The base of the infrared sensor device 30 is, for example, one on which the infrared array sensor 10 or the signal processing chip 37 can be mounted on the inner bottom surface 31a side of the recess of the package 31, and can be made of metal, ceramic, or the like. As a material of the package 31, a high gas barrier property is required for hermetic sealing such as sealing an inert gas or evacuating, and aluminum nitride, alumina, or silica-based ceramic is more preferably used. Note that the substrate is not limited to the configuration such as the package 31 described above, and may be a stem used in a can package.

  The infrared array sensor 10 is made by contacting the metal layer 7 functioning as an etching mask when forming the cavity 5 of the infrared array sensor 10 with the metal pattern 32 provided on the inner bottom surface 31a of the concave portion of the package 31, The layer 7 and the metal pattern 32 are directly connected and electrically connected by diffusion bonding. Since the metal layer 7 and the metal pattern 32 are diffusion-bonded, unnecessary gas is not generated inside the infrared sensor device 30 when the infrared array sensor 10 is mounted on the package 31.

  The signal processing chip 37 is flip-chip mounted on the metal patterns 38 and 38 provided on the inner bottom surface 31 a of the recess of the package 31 using metal bumps 36 and 36. As a result, the signal processing chip 37 is fixed to the metal patterns 38 and 38 and is electrically connected and mounted. The signal processing chip 37 may be bonded and fixed by diffusion bonding in the same manner as the metal layer 7 of the infrared array sensor 10 is mounted on the metal pattern 32 provided on the package 31.

  The package 31 on which the infrared array sensor 10 and the signal processing chip 37 are mounted has a lid 33 provided with a lens-shaped infrared transmitting member 34 for allowing infrared rays to enter the infrared array sensor 10 as a cover. Are hermetically sealed. In order to firmly join the lid 33 and the package 31 with good airtightness, resistance seam welding can be used. Therefore, a seam ring (not shown) made of, for example, Kovar is provided on the concave portion of the package 31 so that the lid 33 and resistance seam welding can be performed. When resistance seam welding is performed, it is preferable that a seam welding metal film (for example, a W film, a Ni plating film, an Au plating film, or the like) is formed in advance on the package 31 in contact with the seam ring.

  The shape of the package 31, the metal pattern 32 provided on the package 31 to be bonded to the metal layer 7 of the infrared array sensor 10, the metal patterns 38 and 38 to be flip-chip mounted on the signal processing chip 37, and the metal pattern 38 penetrating the package 31. The through electrodes, the external electrodes 35 and 35 provided outside the package 31 and a part of the seam welding metal film can be formed simultaneously with the firing of the package 31.

  Next, the cover used for the infrared sensor device 30 of the present embodiment can be hermetically sealed to the package 31 surrounding the infrared array sensor 10 mounted on the package 31. The lid 33 serving as a cover has an opening 33a serving as a window with respect to the infrared array sensor 10 mounted on the inner bottom surface 31a side of the recess of the package 31, and the infrared array sensor so as to seal the opening 33a. A lens-shaped infrared transmitting member 34 for allowing infrared rays to enter 10 is hermetically bonded. The cover is not limited to the lid 33 that seals the package 31, but may be a cap used in a can package. Further, the cover and the base body may each be a plate-like member, and may have a structure in which a cylindrical spacer capable of accommodating the infrared array sensor 10 is interposed. Further, a cap made of a ceramic material provided with an infrared transmitting member 34 may be used as a cover, and the infrared array sensor 10 mounted on a metal base may be surrounded and hermetically sealed.

  The lid 33 is preferably one that shields unnecessary electromagnetic waves that cause noise on the infrared array sensor 10 and can be hermetically bonded. When the lid 33 and the package 31 are seam welded, the lid 33 has conductivity. It is preferable to have. As a material for the lid 33, Kovar, stainless steel, iron, or the like can be used. In addition, the shape of the opening part 33a provided in the lid 33 can be variously formed as desired, such as a circle, an ellipse, a square, and a rectangle.

  Further, when the lid 33 is seam welded to the package 31, it is preferable to provide a Ni plating layer on the surface of the lid 33 where the lid 33 contacts the package 31 or the seam ring. However, the lid 33 provided with the Ni plating layer is likely to be oxidized in a high temperature atmosphere of 350 ° C. or more, which may increase the surface resistance and cause seam welding failure. Therefore, the lid 33 and the infrared transmitting member 34 are hermetically bonded in advance using a low melting point glass or the like in a high temperature atmosphere. In this way, even when the lid 33 is seam welded to the package 31, the surface of the lid 33 (Ni-plated) is obtained because the infrared transmitting member 34 is hermetically sealed in a vacuum atmosphere or an inert atmosphere when bonded to the lid 33. Layer) can be prevented from being oxidized.

  The infrared transmitting member 34 used in the infrared sensor device 30 of the present embodiment is joined so as to seal the opening 33a of the lid 33, and is formed in a convex lens shape as shown in FIG. The lens shape of the infrared transmitting member 34 is not limited to a convex lens, and may be, for example, a concave lens, a cylindrical lens, an elliptical spherical lens, a Fresnel lens, or a diffractive lens.

  Moreover, as a material of the infrared transmitting member 34, a semiconductor material such as Si, Ge, ZnS, and ZnSe that can transmit infrared rays is preferably used, but is not limited thereto. In addition, in order to make the infrared transmissive member 34 into a lens shape, for example, it can be formed by a method for forming a semiconductor lens using an anodizing technique.

  More specifically, in order to form a semiconductor lens that becomes the infrared transmitting member 34 by applying an anodizing technique (see, for example, Japanese Patent No. 3897056), an anode having a pattern designed according to a desired lens shape is a semiconductor. A substrate (eg, a silicon substrate) is formed on one surface side so as to be in ohmic contact with the semiconductor substrate. For example, in order to form the convex lens-shaped infrared transmitting member 34 shown in FIG. 1C, a conductive layer serving as a base of an anode is formed on the one surface of the semiconductor substrate, and then the conductive layer is formed on the conductive layer. Patterning is performed so that a part opened in a circular shape is provided and a part of the one surface of the semiconductor substrate is exposed in a circular shape.

  Next, the entire region where the porous portion is to be formed on the other surface of the semiconductor substrate is immersed in an electrolytic solution capable of etching away oxides of constituent elements of the semiconductor substrate.

  Thereafter, a current is passed between the cathode and the anode disposed opposite to the other surface side of the semiconductor substrate to form a porous portion having a desired shape on the other surface side of the semiconductor substrate by oxidation. Subsequently, by removing the porous portion formed on the semiconductor substrate by etching or the like, the infrared transmitting member 34 having a convex lens shape can be formed.

  Instead of the anode having a pattern designed according to a desired lens shape, an insulating layer having a pattern designed according to a desired lens shape is formed on one surface side of the semiconductor substrate, and the semiconductor substrate having the insulating layer A conductive layer is formed on one surface side, or one surface side of the semiconductor substrate having the insulating layer is disposed opposite to the current-carrying electrode via an electrolytic solution, so that the other surface side of the semiconductor substrate is The porous part to be removed can also be formed. Further, if an anode having a rectangular planar shape is formed instead of providing a circular opening in the conductive layer, a plano-concave cylindrical lens can be formed as the infrared transmitting member 34.

  Such an infrared transmitting member 34 can be hermetically joined with a brazing material, solder, a hermetically sealable resin, low melting point glass, or the like so as to seal the opening 33a of the lid 33. For example, in the case where a semiconductor lens having a convex lens shape using Si capable of transmitting infrared rays is hermetically bonded to the periphery of the opening 33a of the lid 33 as the infrared transmitting member 34 through low-melting glass, a lead-free bismuth system is used. A molded product obtained by preforming a low-melting glass frit into a ring shape can be suitably used.

  Next, the manufacturing process of the infrared sensor device 30 in which the infrared array sensor 10 having the metal layer 7 of the present embodiment is mounted on the inner bottom surface 31a of the recess of the package 31 will be described in order based on FIG.

  In the present embodiment, a package 31 made of an alumina ceramic material having a recess is used as the package 31 of the infrared sensor device 30. A metal pattern 32 having at least a surface made of Au is provided on the inner bottom surface 31 a side of the concave portion of the package 31 so as to be bonded to the metal layer 7 of the infrared array sensor 10. Further, in order to perform flip chip mounting using the signal processing chip 37 and the metal bumps 36 and 36, metal patterns 38 and 38 are formed on the inner bottom surface 31 a side of the recess of the package 31. The metal pattern 38 is electrically connected to external electrodes 35 and 35 provided on the back surface of the package 31 through the through-electrodes penetrating in the thickness direction of the package 31 (FIG. 1A). .

  Next, an infrared sensor element mounting step is performed in which the infrared array sensor 10 having four thermal infrared detection units 25 is mounted on the inner bottom surface 31a side of the package 31 having the concave portion. Specifically, the metal layer 7 of the infrared array sensor 10 is aligned on a metal pattern 32 (for example, an Au film) provided on the package 31 and directly contacted in a vacuum chamber having an argon gas atmosphere inside. And place it. The infrared array sensor 10 is heated at 300 ° C. to 400 ° C. while pressing the infrared array sensor 10 toward the inner bottom surface 31 a side of the recess of the package 31. Thus, the metal layer 7 of the infrared array sensor 10 is directly bonded and mounted to the metal pattern 32 provided on the package 31 by performing AuAu diffusion bonding. The metal layer 7 of the infrared array sensor 10 and the metal pattern 32 of the package 31 are also electrically connected (FIG. 1B).

  Diffusion bonding is a method in which the base material is brought into close contact with the base material at a temperature equal to or lower than the melting point of the base material, and pressure is applied to the extent that plastic deformation does not occur as much as possible. . Therefore, unlike mounting using an adhesive such as solder or resin, it can be directly joined as it is solid. As a result, the vertical positional relationship of the infrared array sensor 10 with respect to the inner bottom surface 31a of the recess of the package 31 does not substantially change before and after joining. Therefore, the infrared array sensor 10 can be mounted on the inner bottom surface 31a side of the recess of the package 31 with high accuracy. Accordingly, in diffusion bonding, bonding may be performed at normal temperature (for example, 25 ° C.) according to the material to be bonded, or may be bonded while heating. When diffusion bonding is performed at room temperature, for example, before bonding, the bonding surfaces are irradiated with argon plasma, an ion beam or an atomic beam in a vacuum to activate each bonding surface, and then the bonding surfaces are brought into contact with each other. What is necessary is just to join. Such diffusion bonding at room temperature is more preferable in that stress is relaxed when the infrared array sensor 10 and the package 31 are directly bonded.

  In addition, in order to improve the joint strength between the infrared array sensor 10 and the package 31, it is more preferable to provide an activation process for cleaning the surface of the inside of the recess of the package 31 prior to diffusion bonding. When it is desired to align the infrared array sensor 10 with high accuracy in the planar direction of the inner bottom surface 31a of the recess of the package 31, an alignment mark is previously formed on the infrared array sensor 10 and the package 31, respectively. By mounting and joining the array sensor 10 and the package 31 along the alignment mark, the array sensor 10 and the package 31 can be mounted and arranged with high accuracy even in the planar direction.

  Next, the electrodes (not shown) of the signal processing chip 37 and the metal patterns 38 and 38 provided on the package 31 are connected and fixed using metal bumps 36 and 36.

  In this embodiment, the inside of the recess of the package 31 is subjected to ashing after diffusion-bonding the metal layer 7 of the infrared array sensor 10 to the metal pattern 32 provided on the inner bottom surface 31a of the recess of the package 31. Organic matter has been removed. The signal processing chip 37 may remove unnecessary organic substances simultaneously with the infrared array sensor 10 and the package 31, or may separately remove organic substances. The ashing process can be applied as needed depending on the size, number, and materials used of the infrared array sensor 10 and the signal processing chip 37 arranged in the package 31. For example, as the photo-excited ashing, an ozone ashing apparatus or a plasma ashing process can be used. The device can be used.

Subsequently, the lid 33 having the lens-shaped infrared transmitting member 34 is seam-welded so as to hermetically seal the inside of the concave portion of the ashed package 31. Specifically, in order to hermetically join the lid 33 and the infrared transmitting member 34 in advance, the infrared rays are formed so that the opening 33a is closed at the end of the opening 33a of the lid 33 via a preform molded product of low melting point glass. The transmissive member 34 is overlapped. After removing the unnecessary binder in the preform molded product of the low melting point glass, the lid 33 is heated to the firing temperature of the low melting point glass in an inert atmosphere such as a vacuum atmosphere or an N ₂ gas atmosphere to prevent oxidation of the lid 33. The lid 33 and the infrared transmitting member 34 are hermetically joined by low melting point glass.

  Subsequently, the lid 33 is seam welded in a vacuum atmosphere through a seam ring so as to cover the concave portion of the package 31 on which the infrared array sensor 10 or the like is mounted, and hermetically sealed. The infrared sensor device 30 can be formed by this hermetic sealing process (FIG. 1C).

  The infrared transmitting member 34 and the lid 33 are previously ashed to remove organic substances. Further, instead of hermetically sealing the lid 33 having the infrared transmitting member 34 and the package 31 by seam welding, the lid 33 and the package 31 having the infrared transmitting member 34 are made of low melting point glass, AuSi, solder, or organic type. Then, sealing may be performed using an epoxy resin or the like.

In order to mount the infrared array sensor 10 on the package 31, the infrared sensor device 30 of the present embodiment includes the metal layer 7 of the infrared array sensor 10 provided at the time of forming the infrared array sensor 10 and the recesses of the package 31. The diffusion bonding of the metal pattern 32 provided on the bottom surface 31 is used. Therefore, the focal length of the lens-shaped infrared transmitting member 34 with respect to the infrared array sensor 10 is compared with an infrared sensor device in which the infrared array sensor 10 is aligned with the package 31 and mounted with solder or die bond resin. The position of the infrared array sensor 31 in the vertical direction with respect to the inner bottom surface 31a of the recess of the package 31 rarely changes before and after mounting. Therefore, the infrared sensor device 30 with higher performance can be manufactured with high productivity.
(Embodiment 2)
The basic configuration of the infrared sensor device 30 of the present embodiment is substantially the same as that of the first embodiment, and the metal layer 7 of the infrared array sensor 10 and the metal pattern 32 provided on the inner bottom surface 31a side of the recess of the package 31 are diffusion bonded. Instead, the metal layer 7 of the infrared array sensor 10 and the inner bottom surface 31a of the recess of the package 31 are directly bonded by anodic bonding. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted suitably.

  As shown in FIG. 4, the infrared sensor device of the present embodiment includes an alkali metal that becomes movable ions at high temperature and high voltage so that the package 31 on which the infrared array sensor 10 is mounted can be anodically bonded. It is formed of low temperature co-fired ceramics (hereinafter referred to as “LTTC”) containing glass components.

Ceramic packages based on alumina usually need to be fired at about 1500 ° C, whereas LTCC is fired at a lower temperature, for example 900 ° C or less, by adding a glass-based material to alumina. Can do. Specifically, an aluminosilicate-based (Na ₂ O—Al ₂ O ₃ —Ba ₂ O ₃ —SiO ₂ -based) glass composition can be used as the LTCC material.

  Here, anodic bonding is a processing method in which glass having movable ions and a metal material can be directly closely bonded. For example, the metal layer 7 of the infrared array sensor 10 and the package 31 made of LTC are stacked. In combination, heating is performed at a temperature of several hundred degrees or less, and simultaneously, a DC voltage of several hundred volts is applied between the metal layer 7 side as an anode. Due to the electrostatic attractive force generated at this time, the metal layer 7 of the infrared array sensor 10 can be directly joined to the inner bottom surface 31 a of the recess of the package 31.

  In the present embodiment, the package 31 has an insulating property, and the infrared array sensor 10 is directly bonded to the inner bottom surface 31 a of the recess of the package 31. Therefore, the infrared array sensor 10 and the signal processing chip 37 are electrically connected by wire bonding with a wire (for example, a gold wire or an aluminum wire) 39. Similarly, the signal processing chip 37 is wire-bonded with a metal pattern 38 provided on the inner bottom surface 31a of the recess of the package 31 with a wire 39, and the external electrode 35, 35 is connected from the metal pattern 38 via the through electrode. It is configured to be electrically connectable. The signal processing chip 37 is mounted on the inner bottom surface 31a of the recess of the package 31 with an adhesive (for example, epoxy resin) 36 '.

  In the infrared sensor device 30 of the present embodiment, the infrared array sensor 10 is directly anodically bonded to the inner bottom surface 31 a side of the recess of the package 31 using the metal layer 7 provided when the infrared array sensor 10 is formed. Therefore, the focal length of the lens-shaped infrared transmitting member 34 with respect to the infrared array sensor 10 is compared with an infrared sensor device in which the infrared array sensor 10 is aligned with the package 31 and mounted with solder or die bond resin. The position of the infrared array sensor 31 in the vertical direction with respect to the inner bottom surface 31a of the recess of the package 31 rarely changes before and after mounting. Therefore, the infrared sensor device 30 with higher performance can be manufactured with high productivity.

1 Silicon substrate (substrate)
2 Infrared sensor thin film 3 Silicon wafer (wafer)
5 Cavity 7 Metal layer 10 Infrared array sensor (infrared sensor element)
30 Infrared sensor device 31 Package (base)
32 metal pattern 33 lid (cover)
34 Infrared transmitting member

Claims (4)

An infrared sensor element comprising: an infrared sensor thin film formed on one surface side of the substrate; and a cavity formed on the other surface side of the substrate and spatially separating a part of the infrared sensor thin film from the substrate; A base body on which the infrared sensor element is mounted and a lens-shaped infrared transmitting member that allows infrared light to enter the infrared sensor element are enclosed and hermetically sealed around the infrared sensor element mounted on the base body. A method of manufacturing an infrared sensor device having a cover,
After the infrared sensor thin film is formed on one surface side of the wafer serving as the base of the substrate, a metal layer is formed except at least a cavity forming region for forming the cavity on the other surface side of the wafer, An infrared sensor element forming step of forming the infrared sensor element by etching the cavity forming region from the other surface side of the wafer using the metal layer as a mask;
An infrared sensor element mounting step of mounting the infrared sensor element on the base by directly contacting and joining the metal layer of the infrared sensor element and the base;
A method of manufacturing an infrared sensor device, comprising: a hermetically sealing step of surrounding the infrared sensor element mounted on the substrate by the cover and hermetically sealing the substrate.   2. The infrared sensor device according to claim 1, wherein in the infrared sensor element mounting step, the metal layer of the infrared sensor element and the metal pattern formed on the base are directly bonded by diffusion bonding. Production method.   In the infrared sensor element forming step, the metal layer is formed by forming the metal layer after penetrating a through-wiring through which the output from the infrared sensor thin film can be taken out in the thickness direction of the wafer serving as the base of the substrate. And the through wiring, and in the infrared sensor element mounting step, the metal layer and the metal pattern are electrically connected by diffusion bonding the metal layer and the metal pattern. The manufacturing method of the infrared sensor apparatus of Claim 2. 2. The method of manufacturing an infrared sensor device according to claim 1, wherein in the infrared sensor element mounting step, the metal layer of the infrared sensor element and the base are directly bonded by anodic bonding.

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