JP6696884B2 - Substrate for mounting electronic element and electronic device - Google Patents

Description

  The present invention relates to an electronic element mounting substrate and an electronic device on which an electronic element is mounted.

  Conventionally, an electronic device in which an electronic device such as a CCD (Charge Coupled Device) type or a CMOS (Complementary Metal Oxide Semiconductor) type imaging device or an electronic device such as a light emitting device such as an LED (Light Emitting Diode) is mounted on an electronic device mounting substrate. It has been known. Such electronic devices are used by being attached to various devices such as personal digital assistants and home appliances. In the mobile terminal device described in Patent Document 1, the image pickup element is connected to the circuit board via the support member, and the circuit board is fixed to the inner surface of the housing.

JP, 2005-107295, A

  In the mobile terminal device described in Patent Document 1, for example, when the circuit board or the supporting member is made of a ceramic material, the circuit board or the supporting member may be damaged when an impact is applied to the housing from the outside. ..

An electronic element mounting substrate according to one aspect of the present invention is a rectangular plate-shaped ceramic wiring board made of a ceramic material, and has a mounting area in which an electronic element is mounted and a rectangular parallelepiped-shaped lid member covering the mounting area. A ceramic wiring board having a first surface including a rectangular annular bonding area to be bonded;
A pillow portion provided on a second surface of the ceramic wiring board, which is opposite to the first surface, and has the shortest distance from the center of the first surface of the four sides of the outer shape of the bonding area in plan view. A pillow portion having a strip-shaped portion arranged along the one side is provided at a position overlapping with the one side.

Further, an electronic device according to one aspect of the present invention includes the electronic element mounting substrate described above,
An electronic element mounted in the mounting area,
A lid member joined to the joining region.

  According to the electronic element mounting board of one aspect of the present invention, by providing the pillow portion, deformation of the housing in which the electronic element mounting board is accommodated is suppressed, and damage to the ceramic wiring board is suppressed.

  Further, according to the electronic device of one aspect of the present invention, the reliability can be improved by using the electronic element mounting substrate.

FIG. 3 is a plan view of an electronic element mounting substrate and an electronic device according to an embodiment of the present invention. It is a top view of the electronic device mounting substrate concerning the embodiment of the present invention. It is sectional drawing which makes the AA line of FIG. 1 a cutting plane line. FIG. 3 is a bottom view of the electronic element mounting substrate and the electronic device according to the embodiment of the present invention. FIG. 6 is a bottom view of an electronic element mounting substrate and an electronic device according to another embodiment of the present invention. FIG. 9 is a bottom view of an electronic element mounting substrate and an electronic device according to still another embodiment of the present invention. FIG. 9 is a bottom view of an electronic element mounting substrate and an electronic device according to still another embodiment of the present invention.

  Hereinafter, some exemplary embodiments of the present invention will be described with reference to the drawings. In the following description, a configuration in which an electronic element is mounted on an electronic element mounting substrate will be referred to as an electronic device. The electronic element mounting substrate and the electronic device may be either upside or downside, but for convenience, the orthogonal coordinate system xyz is defined and the positive side in the z direction is upside. Or use the word on the bottom.

  An electronic device 21 and an electronic element mounting substrate 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. The electronic device 21 according to the present embodiment includes the electronic element mounting substrate 1, the lens holder 5, and the electronic element 10.

  FIG. 1 is a plan view of an electronic element mounting substrate and an electronic device according to an embodiment of the present invention. FIG. 2 is a plan view of the electronic element mounting substrate according to the embodiment of the present invention. FIG. 3 is a sectional view taken along the line AA in FIG. FIG. 4 is a bottom view of the electronic element mounting substrate and the electronic device according to the first embodiment of the present invention.

  In the examples shown in FIGS. 1 to 4, the electronic element mounting substrate 1 includes a rectangular plate-shaped ceramic wiring substrate 6 and a pillow portion 9 provided on the ceramic wiring substrate 6. The ceramic wiring board 6 is made of a ceramic material and has a first surface 6c including a mounting area 6a on which the electronic element 10 is mounted and a bonding area 6b on which the lens holder 5 as a lid member is bonded. Has a second surface 6d opposite thereto. The pillow portion 9 is provided on the second surface 6d opposite to the first surface 6c to which the lens holder 5 is joined.

  In the present embodiment, the first surface 6c of the ceramic wiring board 6 is provided with a recess (cavity) 6e including the mounting area 6a of the electronic element 10. Around the recess 6e, a connection pad 3 that is electrically connected to the electronic element 10 is provided, and for example, a bonding wire 11 is used to electrically connect the electronic element 10 and the connection pad 3. Used. Further, the first surface 6c is provided with an external connection pad 4 that is electrically connected to an external device such as a flexible substrate. The external connection pads 4 are connected to the respective connection pads of the flexible board by a bonding material such as solder. In addition to the connection pads 3 and the external connection pads 4, circuit elements such as resistance elements and capacitor elements may be mounted on the first surface 6c of the ceramic wiring board 6 via the circuit element connection pads.

  In the ceramic wiring board 6, wiring conductors are formed on an insulating layer made of a ceramic material. The ceramic wiring board 6 may be formed of one insulating layer, or may be formed by laminating a plurality of insulating layers of two layers or three layers or more.

  Inside the ceramic wiring board 6, a wiring conductor composed of a through conductor penetrating each insulating layer and an internal wiring may be provided. The ceramic wiring board 6 may be provided on the first surface 6c or the second surface 6d. It may have an exposed wiring conductor. Further, the ceramic wiring board 6 may be provided with external connection electrodes for electrically connecting to an external board, an external circuit, or the like on the first surface 6c, the second surface 6d, the side surface, and the like.

  Examples of the ceramic material used in the ceramic wiring board 6 of the present embodiment include an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, and a silicon nitride sintered body. Examples include a body or a glass ceramic sintered body.

  The connection pad 3, the external connection pad 4, and the wiring conductor provided on the ceramic wiring board 6 are, for example, tungsten (W), molybdenum (Mo), manganese (Mn), silver (Ag) or copper (Cu), or It is made of an alloy or the like containing at least one metal material selected from these.

  A plating layer is preferably provided on the exposed surfaces of the connection pads 3, the external connection pads 4 and the wiring conductors provided on the ceramic wiring board 6. By providing the plating layer, the exposed surface of each pad and the wiring conductor can be protected and oxidation can be prevented. Further, by providing the plating layer, good electrical connection between the connection pad 3 and the electronic element 10 via the bonding wire 11 or the like can be achieved. As the plating layer, for example, a Ni plating layer having a thickness of 0.5 to 10 μm may be applied. Alternatively, a gold (Au) plating layer having a thickness of 0.5 to 3 μm may be further deposited on the Ni plating layer.

  The lens holder 5, which is a lid member, is joined and fixed to the joining region 6b of the first surface 6c of the ceramic wiring board 6. The lens holder 5 is provided so as to cover the mounting area 6a, that is, to cover the mounted electronic element 10.

  The lens holder 5 has an optical lens 7 and a lens holding portion 50 that holds the optical lens 7 such that the optical axis of the optical lens 7 passes through the mounting area 6a. The lens holder 5 may further include an optical filter 8 such as an IR filter provided on the optical axis. As the optical lens 7, a lens having various shapes such as a convex lens, a concave lens or a Fresnel lens can be used. The optical lens 7 may have various optical functions according to the type of the electronic element 10 mounted on the electronic element mounting substrate 1. For example, when the electronic element 10 is an image pickup element or a light receiving element, it is externally supplied. The electronic device 10 has a function of focusing incident external light on the surface of the image pickup device and converging, diverging or collimating outgoing light emitted from the light emitting device when the electronic device 10 is a light emitting device.

  The lens holder 5 has a generally rectangular parallelepiped shape with one surface open, and the ceramic wiring board is laid down so that the opened surface is closed by the first surface 6 c of the ceramic wiring board 6. It is joined to 6. Since the lens holder 5 has a rectangular parallelepiped shape, the bonding area 6b of the first surface 6c has a rectangular ring shape.

  The lens holding unit 50 is made of a resin material such as PBT (polybutylene terephthalate). The lens holding part 50 is provided with a through hole 50a in the upper half portion of the lens holder 5, and the optical lens 7 is held so as to fit into the through hole.

  The lower end of the lens holder 5 is directly fixed to the bonding area 6b of the first surface 6c of the ceramic wiring board 6. Here, being directly fixed means that the lower end of the lens holder 5 and the first surface 6c of the ceramic wiring substrate 6 are fixed by a fixing material such as an adhesive. Since the lens holder 5 including the lens holding portion 50 is made of a resin material and the ceramic wiring board 6 is made of a ceramic material, the adhesive for fixing these may be an adhesive that can bond the resin and the ceramic material. For example, an epoxy resin adhesive or an acrylic resin adhesive can be used.

  The pillow portion 9 is a mesa-shaped portion provided on the second surface 6d and protruding from the second surface 6d. The pillow portion 9 has a center side at a position overlapping with one side (hereinafter, referred to as a “center side side”) 60 that is closest to the center of the first surface 6c among the four sides of the outer shape of the joining region 6b in a plan view. It has a strip portion 90 arranged along the side 60. In the present embodiment, the pillow portion 9 is composed of only the strip portion 90.

  Since the strip-shaped portion 90 is arranged at a position overlapping the center side 60 of the joining region 6b, it is also provided at a position close to the center on the second surface 6d. In the present embodiment, the first surface 6c and the second surface 6d have a rectangular shape, the bonding region 6b has a rectangular annular shape, and the respective sides are parallel to each other. In addition, the bonding region 6b is located so as to be biased toward the one end portion in the longitudinal direction of the first surface 6c, that is, the short side, and one side 61 of the bonding region 6b is close to the short side of the first surface 6c. One side facing the one side 61 close to the short side is the center side 60 having the shortest distance from the center of the first surface 6c. The strip-shaped portion 90 of the pillow portion 9 is arranged along the center side 60 at a position overlapping the center side 60 in a plan view.

  The pillow portion 9 is located between the ceramic wiring board 6 and the casing of the mobile terminal device when the electronic device 21 including the electronic element mounting substrate 1 is assembled in a device such as a mobile terminal device. If the pillow portion 9 is not provided, the ceramic wiring board 6 is directly fixed to the inner wall of the housing of the mobile terminal device. When an impact force is applied from the outside, the housing is bent and deformed, and the impact force is transmitted to the ceramic wiring board 6 and damaged. Since the pillow portion 9 is provided, the impact force is concentrated on the pillow portion 9. Since the lens holder 5 is joined to the opposite side of the pillow portion 9 with the ceramic wiring board 6 sandwiched therebetween, the pillow portion 9, the ceramic wiring board 6 and the lens holder 5 integrally receive the impact force so that the housing Deformation is suppressed. As a result, damage to the ceramic wiring board 6 is suppressed.

  The pillow portion 9 needs to have a hardness enough to receive an impact force from the outside as described above. If the hardness of the pillow portion 9 is small and easily deformed, the housing is bent by the impact force and the ceramic wiring board 6 is damaged. The characteristic of the pillow portion 9 is, for example, Young's modulus of 1 GPa or more and 500 GPa or less.

  As the material used for the pillow portion 9, any material may be used as long as the Young's modulus is within the above range, and a ceramic material may be used similarly to the ceramic wiring board 6 or a resin material may be used. Good. Examples of the resin material include polyethylene terephthalate, polycarbonate and polyurethane.

  When the width of the strip-shaped portion 90 is W (mm) and the distance between the side 60 overlapping the strip-shaped portion 90 and the side 61 parallel to the side 60 of the outer shape of the joining region 6b is L (mm), 0.05 ≦ (W / L) ≦ 0.25. Furthermore, 0.05 ≦ (W / L) ≦ 0.25 may be satisfied, and W / L = 0.25 can be satisfied. The distance L is the width of the bonding region 6b, that is, the width of the lens holder 5. W / L is the ratio of the band-shaped portion 90 to the width of the lens holder 5 in plan view.

  Based on the simulation result, when W / L = 0.25, that is, the ratio of the width of the lens holder 5 occupied by the strip portion 90 is ¼, the ceramic wiring when a constant external force is applied to the housing. It was found that when the force applied to the substrate 6 was the smallest and W / L was smaller than 0.25, the force applied to the ceramic wiring substrate 6 was large. If W / L is larger than 0.25, the force applied to the ceramic wiring board 6 increases rapidly. Therefore, by setting W / L within the above range, the force applied to the ceramic wiring board 6 can be suppressed. it can.

  In the present embodiment, the length of the strip portion 90 is substantially the same as the short side length of the second surface 6d of the ceramic wiring board 6. The length of the strip portion 90 may be shorter than the short side length of the second surface 6d of the ceramic wiring board 6. For example, the length of the strip-shaped portion 90 can be 1/6 or more of the length of the short side of the second surface 6d.

  FIG. 5 is a bottom view of an electronic element mounting substrate and an electronic device according to another embodiment of the present invention. The present embodiment is the same as the above embodiment except that the length of the strip portion 90 is ⅙ of the short side length of the second surface 6d, and thus detailed description thereof will be omitted. In this embodiment as well, the pillow portion 9 is composed only of the band-shaped portion 90. In the present embodiment, the strip-shaped portion 90 is arranged at a position overlapping the center side 60 in the plan view, along the center side 60, and in the center of the second surface 6d in the lateral direction. By arranging in the center in the lateral direction, even if the length of the strip-shaped portion 90 is relatively short, deformation of the housing is suppressed even when an external impact force is applied, and damage to the ceramic wiring board 6 is suppressed. To be done.

  FIG. 6 is a bottom view of an electronic element mounting substrate and an electronic device according to still another embodiment of the present invention. In the present embodiment, the strip-shaped portion 90 is composed of a plurality of divided portions arranged at intervals in the extending direction. If the plurality of divided portions are arranged along the central side 60 at a position overlapping the central side 60 in a plan view, the intervals between the divided portions and the lengths of the divided portions are the same. May be different. The number of divided portions may be two or more.

  In the present embodiment, as shown in FIG. 6, the strip-shaped portion 90 is composed of, for example, two divided portions 90a. The two divided portions 90a are arranged along the center side 60 at a position overlapping the center side 60 in a plan view. The two divided portions 90a may be arranged so as to be located at the center of the second surface 6d in the lateral direction, or may be arranged one at each end of the second surface 6d in the lateral direction. In the example shown in FIG. 6, they are arranged at both ends in the lateral direction. In this way, the plurality of divided portions may be arranged symmetrically with respect to the center of the center side 60.

  FIG. 7 is a bottom view of an electronic element mounting substrate and an electronic device according to still another embodiment of the present invention. In the present embodiment, the pillow portion 9 is provided at a position overlapping the center side 60 in a plan view, in addition to the strip-shaped portions 90 arranged along the center-side side 60, from the both ends of the strip-shaped portion 90 to the center. It further has two orthogonal portions 91 extending along the two sides orthogonal to the side edge 60. By providing the orthogonal portion 91, deformation of the housing is suppressed and damage to the ceramic wiring board 6 is suppressed by receiving the force applied to the bonding region 6b among the impact forces applied from the outside. The length of the orthogonal portion 91 may be 10 to 80% of the width L of the bonding region 6b.

  As the electronic element 10, for example, an image pickup element such as a CCD type or a CMOS type, a light emitting element such as an LED, a light receiving element such as a photodetector, a semiconductor memory element, or an arithmetic element such as an ASIC (an integrated circuit for a specific application) is used. In the example shown in FIGS. 2 and 3, each electrode of the electronic element 10 is electrically connected to the connection pad 3 provided on the ceramic wiring board 6 by the bonding wire 11. For electrical connection between the electronic element 10 and the ceramic wiring substrate 6, gold bumps or solders may be used instead of the bonding wires. Further, the electronic element 10 is adhesively fixed to the ceramic wiring board 6 via a fixing material 12 such as a brazing material.

  When the electronic element 10 is an image pickup element, the focal length from the optical lens 7 to the light receiving surface of the image pickup element surface is determined by the optical lens 7 and the image pickup element used. Further, the lower the height of the lens holder 5, the lower the height of the electronic device 21 and the height can be reduced.

  By having the electronic element mounting substrate 1 having the above configuration, the lens holder 5, and the electronic element 10, it is possible to provide the electronic device 21 having high reliability.

  Next, an example of a method of manufacturing the electronic device 21 of the present embodiment will be described. An example of the manufacturing method shown below is a manufacturing method using a multi-cavity wiring board.

(1) First, a ceramic green sheet forming the ceramic wiring board 6 is formed. For example, when the ceramic wiring substrate 6 which is an aluminum oxide (Al ₂ O ₃ ) sintered body is obtained, Al ₂ O ₃ powder is used as a sintering aid such as silica (SiO ₂ ), magnesia (MgO) or calcia. Powder such as (CaO) is added, and further a suitable binder, solvent and plasticizer are added, and then a mixture of these is kneaded to form a slurry. Then, a ceramic green sheet for multi-cavity production is obtained by a conventionally known forming method such as a doctor blade method or a calendar roll method.

  (2) Next, by a screen printing method or the like, a metal is applied to the ceramic green sheet obtained in the above step (1) on the portion to be the connection pad 3, the external connection pad 4, and the wiring conductor including the through conductor and the internal wiring. Apply or fill with paste.

  This metal paste is prepared by adding an appropriate solvent and a binder to the metal powder made of the above-mentioned metal material and kneading the mixture to adjust the viscosity to an appropriate level. The metal paste may contain glass or ceramics in order to enhance the bonding strength with the ceramic wiring board 6.

  (3) Next, the green sheet described above is processed by a mold or the like. A through hole is formed in the central portion of the green sheet that becomes the ceramic wiring board 6, and the whole is frame-shaped.

  (4) Next, the ceramic green sheets to be the insulating layers are laminated and pressed to produce a ceramic green sheet laminated body to be the ceramic wiring board 6. Further, in this step, for example, after the green sheet laminated body to be the respective layers of the ceramic wiring board 6 is separately produced, both are laminated and pressed to form the green sheet laminated body to be the ceramic wiring board 6. You may produce.

  (5) Next, the ceramic green sheet laminate is fired at a temperature of about 1500 to 1800 ° C. to obtain a multi-cavity wiring board in which a plurality of ceramic wiring boards 6 are arranged. By this step, the above-mentioned metal paste is fired at the same time as the ceramic green sheet that becomes the ceramic wiring board 6, and becomes the connection pad 3, the external connection pad 4, or the wiring conductor.

  (6) Next, the multi-cavity wiring board obtained by firing is divided into a plurality of ceramic wiring boards 6. In this division, a dividing groove is formed in the multi-cavity wiring board along a portion which becomes an outer edge of the ceramic wiring board 6, and the ceramic wiring board 6 is broken along the dividing groove to divide, or by a slicing method or the like. It is possible to use a method such as cutting along the outer edge of the wiring board 6. Incidentally, the dividing groove can be formed by cutting after firing with a slicing device to have a thickness smaller than that of the multi-cavity wiring board, or by pressing a cutter blade on the ceramic green sheet laminate for the multi-cavity wiring board, It may be formed by cutting with a slicing device to a thickness smaller than the thickness of the ceramic green sheet laminate.

  (7) Next, the pillow portion 9 is formed on the second surface 6d of the ceramic wiring board 6. The pillow portion 9 may be formed by adhering a resin material or a ceramic material processed in advance to the shape of the pillow portion 9 to a predetermined position on the second surface 6d of the ceramic wiring board 6 with an adhesive or the like. When the pillow portion 9 is made of a resin material, the resin material may be applied to the predetermined position on the second surface 6d of the ceramic wiring board 6 in the shape of the pillow portion 9 and then cured. When the pillow portion 9 is made of a ceramic material, the ceramic green sheet is cut into a shape of the pillow portion 9, and the pillow portion 9 is laminated at a predetermined position of the laminated body to be the ceramic wiring board 6 and integrated by co-firing. The part 9 may be formed.

  (8) Next, the electronic element 10 is mounted in the mounting region 6a, and each electrode of the electronic element 10 and the connection pad 3 are electrically connected by wire bonding.

  (9) The lens holder 5 is bonded to the bonding area 6b of the ceramic wiring board 6. An adhesive is applied to either or both of the lower end of the lens holder 5 and the bonding area 6b of the ceramic wiring substrate 6 to bond them together.

  The electronic device 21 is obtained by the steps (1) to (9). The order of steps (1) to (9) is not limited to the above order.

  In the above-described embodiment, the recessed portion 6e is provided on the first surface 6c of the ceramic wiring substrate 6 to mount the electronic element 10. However, for example, the recessed portion 6e is not provided according to the focal length and the like, and the flat first surface 6c is provided. The electronic element 10 may be mounted as the surface 6c.

  Further, the arrangement, number, shape, etc. of the connection pads 3 in each of the above-described embodiments are not particularly limited.

  The present invention is not limited to the examples of the above-described embodiments, and various modifications such as numerical values are possible.

1 Electronic Element Mounting Substrate 3 Connection Pad 4 External Connection Pad 5 Lens Holder 6 Ceramic Wiring Board 6a Mounting Area 6b Bonding Area 6c First Surface 6d Second Surface 6e Recess 7 Optical Lens 8 Optical Filter 9 Pillow 10 Electronic Element 11 Bonding Wire 12 Fixing material 21 Electronic device 50 Lens holding part 50a Through hole 60 Center side 90 Band-shaped part 90a Divided part 91 Orthogonal part

Claims (7)

A rectangular plate-shaped ceramic wiring board made of a ceramic material, the first surface including a mounting area in which an electronic element is mounted and a rectangular ring-shaped bonding area to which a rectangular parallelepiped-shaped lid member covering the mounting area is bonded. A ceramic wiring board having
A pillow portion provided on a second surface of the ceramic wiring board, which is opposite to the first surface, and has the shortest distance from the center of the first surface of the four sides of the outer shape of the bonding area in plan view. An electronic element mounting substrate, comprising: a pillow portion having a band-shaped portion arranged along the one side at a position overlapping the one side.   When the width of the strip-shaped portion is W and the distance between the one side of the bonding region and one side parallel to the one side is L, 0.05 ≦ (W / L) ≦ 0.25. The electronic element mounting substrate according to claim 1.   3. The electronic element mounting substrate according to claim 1, wherein the strip-shaped portion is composed of a plurality of divided portions which are arranged at intervals in the extending direction.   3. The electronic device according to claim 1, wherein the pillow portion further has two orthogonal portions extending from both end portions of the strip-shaped portion along two sides orthogonal to the one side of the joining region. Substrate for mounting elements.   The electronic device mounting board according to claim 1, wherein the pillow portion is made of any one of polyethylene terephthalate, polycarbonate and polyurethane. An electronic element mounting substrate according to any one of claims 1 to 5,
An electronic element mounted in the mounting area,
An electronic device comprising: a lid member joined to the joining region. The electronic device includes an image pickup device, a light emitting device or a light receiving device,
The electronic device according to claim 6, wherein the lid member includes a lens, and a lens holding unit that holds the lens so that an optical axis of the lens passes through the electronic element.