JP2011035476A - Imaging module, imaging apparatus and method of manufacturing imaging module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging module to which an imaging element is fixed in parallel to a substrate, an imaging apparatus, and a method of manufacturing the imaging module. <P>SOLUTION: The imaging module includes a substrate 2 on which a recessed part 24 is formed on a mounting surface 21 and an electrode for external connection is provided in the recessed part 24; the imaging element 3 mounted on the mounting surface 21 of the substrate 2; and a solder ball 4 for bonding the substrate 2 and the imaging element 3. In the state in which the substrate 2 and the imaging element 3 are bonded through the solder ball 4, a pair of end parts 33 opposing each other across the recessed part 24 at least of the substrate side surface 32 of the imaging element 3 are in surface contact with the mounting surface 22 surrounding the recessed part 24 of the substrate 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging module and an imaging apparatus in which an imaging element is bonded to a substrate via a solder ball, and an imaging module manufacturing method.

Generally, an imaging module has a configuration in which an imaging element is mounted on one surface of a substrate. An optical lens is disposed on the light receiving surface side of the image sensor, and light incident from the optical lens is imaged by the image sensor. An electric circuit of the image sensor is formed on the substrate, and the substrate and the image sensor are structurally and electrically connected.
One method of surface mounting an image sensor on a substrate is to join the image sensor to the substrate via a solder ball. For example, BGA (Ball grid array), CSP (Chip size)
This is a mounting method often used for semiconductor packages, as represented by package).

  As shown in FIG. 9A, an imaging module 101 employing this mounting method forms solder balls 104 in a grid shape on a substrate 102, and then places an imaging element 103 on the substrate 102 with the solder balls 104 interposed therebetween. The image pickup device 103 is fixed and manufactured by disposing it and heating it in a reflow furnace to melt the solder balls 104. For example, Patent Document 1 (International Publication No. WO01 / 048821) discloses an integrated circuit device in which two substrates are electrically connected by solder balls. This includes a configuration in which the first substrate unit and the second substrate unit mounted on the first substrate unit are electrically connected by solder bumps, and between the first substrate unit and the second substrate unit. The plurality of support members for supporting the second substrate unit on the first substrate unit are provided.

International Publication Number WO01 / 048821

  However, in the method of mounting the image sensor on the substrate with solder balls, when the image sensor is fixed to the substrate by reflow, the image sensor 103 is fixed in parallel to the substrate 102 as shown in FIG. There was a problem that the tilt occurred without being performed. This is considered to be largely due to the influence of the variation in the diameter of the solder balls 104 and the reflow conditions. This tilt is not a problem in a semiconductor package in which two substrates are joined as in Patent Document 1 and the like, but in the case of an imaging module, the tilt of the image sensor causes an adjustment of the optical axis corresponding to the tilt. There is a problem that an extra work process occurs in the manufacturing.

Further, as described in Patent Document 1, it is conceivable to provide a support member between two substrates to prevent the substrate from being tilted. In this case, however, an independent member called a support member is required, and the manufacturing cost is reduced. There is a problem that increases. Furthermore, if the dimensional accuracy of the support member and the installation position with respect to the substrate at the time of mounting are shifted, the image sensor is tilted. Therefore, management of these becomes important, and the work process at the time of mounting is increased.
Therefore, it is an object of the present invention to provide an imaging module and an imaging apparatus in which an imaging element is fixed in parallel to a substrate, and a method for manufacturing the imaging module.

  In order to solve the above problems, an imaging module according to the present invention includes a substrate in which a recess is formed on a mounting surface and an external connection electrode is provided in the recess, and an imaging device mounted on the mounting surface of the substrate. A solder ball that joins the substrate and the image sensor, and the substrate and the image sensor are joined via the solder ball, and at least the concave portion of the substrate-side surface of the image sensor. A pair of ends opposed to each other are in surface contact with the mounting surface surrounding the recess of the substrate.

According to the imaging module according to the present invention, the substrate and the imaging element are bonded in a state in which the substrate is provided with a recess and the surface on the substrate side of the imaging element and the mounting surface surrounding the recess of the substrate are in surface contact. The substrate and the image sensor are surely parallel. In particular, even if there is a variation in the size of the solder balls before fusion bonding, the substrate and the image sensor can be bonded in parallel without being affected by this. Thus, by incorporating the optical system with the mounting surface of the substrate as a reference, the optical system is appropriately set even for an image sensor parallel to the substrate, and the optical axis can be easily adjusted.
In addition, since a structure for making the imaging element and the substrate parallel is provided on the substrate side, a simple apparatus configuration and low cost can be achieved without newly using components.
The substrate is formed with an electric circuit, and electronic components for driving an image sensor such as a resistor, a capacitor, and an integrated circuit are mounted as necessary. An external connection electrode such as an electrode pad is provided on the concave portion of the substrate joined by the solder ball or the substrate side surface of the image sensor.

Further, the depth of the recess is 80% or more and 97% or less of the diameter of the solder ball before the substrate and the image sensor are joined.
Thus, by setting the depth of the recesses to 80% or more and 97% or less of the diameter of the solder balls before bonding, when the substrate and the image sensor are bonded, the mounting surface surrounding the recess of the substrate and the image sensor The surface of the substrate side can be reliably brought into surface contact, the distance between adjacent solder balls can be kept constant, and the bonding strength between the image sensor and the substrate can be maintained. The solder ball shrinks by about 10 to 20% in the height direction by melt bonding, but if the depth of the recess is less than 80% of the diameter of the solder ball before joining, the solder ball will be The surface of the image sensor is relatively larger than the recess, and the surface of the image sensor may float from the mounting surface of the substrate, and the image sensor may be inclined. If pressure is applied until the substrate side surface of the image sensor contacts the mounting surface of the substrate to prevent this, the solder balls spread in the width direction of the recesses, and there is a possibility that adjacent solder balls may come into contact with each other. . On the other hand, if the depth of the recess is greater than 97% of the diameter of the solder ball before melt bonding, the contact area between the solder ball and the image sensor may be too small and the bonding strength may be reduced.

Furthermore, the mounting surface that surrounds the concave portion of the substrate and the end portion of the substrate-side surface of the imaging element are in surface contact over the entire circumference of the concave portion.
Thus, the mounting surface surrounding the recess of the substrate and the end of the surface on the substrate side of the image sensor are in surface contact over the entire circumference of the recess, thereby increasing the contact area between the substrate and the image sensor. Parallelism can be kept stable.

In addition, a gap is provided between the end of the imaging element that is not in surface contact with the mounting surface of the substrate and the mounting surface that surrounds the recess of the substrate, so that the recess and the outside of the imaging module communicate with each other. An opening is formed.
Thus, by forming the opening part which connects a recessed part and the exterior, when hardening the solder ball fuse | melted at the time of reflow, a thermal radiation effect can be improved and hardening can be accelerated | stimulated. In addition, even when the imaging module is incorporated in the imaging apparatus, it has an excellent heat dissipation effect, and when the imaging element is driven and generates heat, heat can be radiated from the opening. Further, since the entire periphery of the end of the image sensor is not in surface contact with the mounting surface of the substrate, the package of the image sensor can be reduced. Furthermore, the mounting area of the solder balls can be effectively taken with respect to the substrate side surface.

Furthermore, the optical system holding part fixed to the mounting surface of the substrate and an optical system held by the optical system holding part are included.
Thus, by attaching the optical system holding part holding the optical system to the mounting surface of the substrate, the reference surface of the optical system orthogonal to the optical axis can be used as the mounting surface of the substrate. By making the image sensor parallel to the optical element, the optical axis can be orthogonal to the image sensor.
In addition, an imaging apparatus including an imaging module having the above-described configuration is proposed.

  An imaging module manufacturing method according to the present invention includes: an imaging module manufacturing method in which an imaging module is manufactured by joining a substrate and an imaging element mounted on a mounting surface of the substrate with a solder ball; A concave portion is formed on the mounting surface, and a plurality of the solder balls having a diameter larger than the depth of the concave portion are disposed on the substrate-side surface of the imaging element, and the solder ball is positioned in the concave portion. A step of facing the imaging element; and the mounting of the solder ball by heating and melting, and a pair of ends opposed to each other across at least the concave portion of the substrate-side surface of the imaging element surrounding the concave portion of the substrate A step of bringing the substrate into contact with a surface, a step of bonding the substrate and the imaging device with the solder ball, and a step of curing the solder ball. To.

  According to the method for manufacturing an imaging module according to the present invention, the solder ball disposed on the imaging device is placed in a recess formed on the substrate, and the solder ball is heated and melted after the substrate and the imaging device are opposed to each other. In addition, since the substrate and the image sensor are bonded in a state where the end portion of the substrate side surface of the image sensor and the mounting surface surrounding the recess of the substrate are in surface contact, the substrate and the image sensor are bonded in parallel. Can do. In particular, even if there is a variation in the size of the solder balls before fusion bonding, the substrate and the image sensor can be bonded in parallel without being affected by this. Thus, by incorporating the optical system with the mounting surface of the substrate as a reference, the optical system is appropriately set even for an image sensor parallel to the substrate, and the optical axis can be easily adjusted. In addition, since a structure for making the imaging element and the substrate parallel is provided on the substrate side, a simple apparatus configuration and low cost can be achieved without newly using components.

In addition, the solder ball disposed in the imaging element has a diameter that is greater than or equal to 3% and less than or equal to 25% than the depth of the concave portion of the substrate.
As described above, the solder ball is a solder ball having a diameter that is 3% or more and 25% or less than the depth of the concave portion, so that the mounting surface that surrounds the concave portion of the substrate when the substrate and the image sensor are joined. And the substrate-side surface of the image sensor can be reliably brought into surface contact, the distance between adjacent solder balls can be kept constant, and the bonding strength between the image sensor and the substrate can be maintained.

Further, the substrate is a multilayer substrate, and a through hole is formed in advance in a layer corresponding to the recess among the layers constituting the substrate, and a plurality of layers including the layer in which the through hole is formed are stacked. A step of forming the concave portion to produce the substrate.
Thus, before laminating a multilayer substrate, a through hole is formed in a layer corresponding to the recess in advance, and a plurality of layers including this layer are laminated to produce a substrate, thereby easily forming the recess. It becomes possible to do.

  As described above, according to the present invention, the substrate and the image sensor are joined by the solder balls in a state where the recess is provided in the substrate and the substrate side surface of the image sensor and the mounting surface surrounding the recess of the substrate are in surface contact. Therefore, the substrate and the image sensor are surely parallel. In particular, even if there is a variation in the size of the solder balls before fusion bonding, the substrate and the image sensor can be bonded in parallel without being affected by this. Thus, by incorporating the optical system with the mounting surface of the substrate as a reference, the optical system is appropriately set even for an image sensor parallel to the substrate, and the optical axis can be easily adjusted.

  Further, the depth of the concave portion is set to 80% or more and 97% or less of the solder ball diameter before bonding, or the solder ball diameter is set to be larger than the depth of the concave portion of the substrate by 3% or more and 25% or less. Thus, when the substrate and the image sensor are joined, the mounting surface surrounding the recess of the substrate and the substrate side surface of the image sensor can be reliably brought into surface contact, and the distance between adjacent solder balls can be maintained constant. The bonding strength between the image sensor and the substrate can be maintained.

Furthermore, since the mounting surface surrounding the concave portion of the substrate and the end of the surface on the substrate side of the imaging device are in surface contact over the entire circumference of the concave portion, the contact area between the substrate and the imaging device can be increased, and the substrate and the imaging device are parallel. Can be kept stable.
In addition, by forming an opening that communicates the concave portion of the substrate with the outside, it is possible to enhance the heat dissipation effect and accelerate the curing when the solder ball melted during reflow is cured. In addition, even when the imaging module is incorporated in the imaging apparatus, it has an excellent heat dissipation effect, and when the imaging element is driven and generates heat, heat can be radiated from the opening. In addition, since the entire periphery of the edge of the image sensor is not in surface contact with the mounting surface of the substrate, the package of the image sensor can be reduced. Furthermore, the mounting area of the solder balls can be effectively taken with respect to the substrate side surface.

In addition, by attaching the optical system holding part holding the optical system to the mounting surface of the substrate, the reference surface of the optical system orthogonal to the optical axis can be used as the mounting surface of the substrate. By making the image sensor parallel, the optical axis can be orthogonal to the image sensor.
Furthermore, before laminating a multilayer substrate, a through hole is formed in advance in a layer corresponding to the recess, and a plurality of layers including this layer are laminated to produce a substrate, thereby easily forming the recess. Is possible.

It is a sectional side view of the image pick-up module concerning the embodiment of the present invention, (a) is a figure showing the state before fusion joining, and (b) is the figure showing the state after fusion joining. It is an enlarged view of Fig.1 (a). It is the top view which looked at the image pick-up module from the image pick-up element side (the 1st example). It is the top view (2nd example) which looked at the image pick-up module from the image sensor side. It is the top view (3rd example) which looked at the imaging module from the image sensor side. It is the top view which looked at the image pick-up module from the image sensor side, (a) is the 4th example and (b) is the 5th example. It is a sectional side view of an imaging module provided with an optical system. It is a sectional side view of a multilayer substrate. It is a sectional side view of the imaging module which concerns on a prior art example, (a) is a figure which shows the state before melt-bonding, (b) is a figure which shows the state after melt-bonding.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the shape of the component described in this example is not intended to limit the scope of the present invention, but is merely an illustrative example.
The imaging module and imaging apparatus of the present invention, and the manufacturing method of the imaging module are electronic devices including digital still cameras, small cameras for portable terminals, consumer equipment such as in-vehicle cameras, and industrial equipment such as surveillance cameras and image inspection apparatuses. Used for image equipment system and its manufacture. Further, the imaging module and imaging apparatus of the present invention, and the manufacturing method of the imaging module relate to an apparatus and manufacturing method in which an imaging element is mounted on a substrate with solder balls, and preferably BGA (Ball grid array) mounting, A CSP (Chip size package) implementation is used.

With reference to Fig.1 (a), the structure of the imaging module which concerns on embodiment of this invention is demonstrated.
The imaging module 1 includes a substrate 2, an imaging device 3 that is surface-mounted on the substrate 2, and a solder ball 4 that is disposed between the substrate 2 and the imaging device 3 and that melt-bonds the substrate 2 and the imaging device 3. Prepare.
The image pickup device 3 is a device in which light from the optical system is imaged on the light receiving surface 31 and converted into an electric signal. Specifically, the imaging device 3 includes a semiconductor substrate, and photoelectric conversion including elements such as a CCD (charge coupled device), a CMOS (metal oxide semiconductor device), a photodiode, and a phototransistor on the light receiving surface 31 side of the semiconductor substrate. A device is provided, and a plurality of electrode pads (not shown) as external connection electrodes are provided on the substrate side surface 32. The electrode pad is formed of a metal material such as aluminum or copper.

  The substrate 2 is formed with an electric circuit, and the imaging element 3 is mounted on the mounting surface 21. If necessary, an electronic component for driving the imaging device 3 such as a resistor, a capacitor, and an integrated circuit is mounted on the surface 23 opposite to the mounting surface 21. An insulating film (solder resist or the like) or insulating layers 20a and 20e as shown in FIG. 8 are provided on the mounting surface 21 and the surface 23 opposite to the mounting surface 21 of the substrate 2. The substrate 2 is preferably a multilayer substrate in which insulating layers 20a, 20c, and 20e and conductive layers (wiring layers) 20b and 20d are alternately stacked as shown in FIG. The insulating layers 20a, 20c, and 20e are formed of a resin or a composite material, and the conductive layers 20b and 20d are formed of copper, aluminum, or the like. The conductive layers 20b and 20d are each a well-known multilayer substrate in which an electric circuit is formed, and the layers are electrically connected by a through hole or the like formed in the layer direction of the multilayer substrate.

A recess 24 is formed in the mounting surface 21 of the substrate 2. A plurality of electrode pads or lead electrodes (not shown), which are external connection electrodes, are provided on the bottom surface of the recess 24. The electrode pad or the extraction electrode is formed of a metal material such as aluminum or copper.
The solder balls 4 are arranged in a grid on the substrate-side surface 32 of the image sensor 3. Note that a solder material composed mainly of Pb and Sn or a lead-free solder material is used as the material of the solder ball. The solder ball 4 is formed on the electrode pad or the extraction electrode provided on the substrate side surface 32 of the image pickup device 3. The solder balls 4 are arranged so as to be located in the recesses 24 of the substrate 2 when the imaging device 3 is mounted on the substrate 2.

  The solder balls 4 are melted by a reflow furnace to become substantially columnar as shown in FIG. 1B, and join the substrate 2 and the image pickup device 3 together. When the imaging device 3 is mounted on the substrate 2, at least a part of the mounting surface 22 surrounding the recess 24 of the substrate 2 is opposed to the substrate-side surface 32 of the imaging device 3 with at least the recess 24 interposed therebetween. 33 makes surface contact. That is, at least two portions 22 of the mounting surface surrounding the recess 24 of the substrate 2 that face each other with at least the recess 24 interposed therebetween are in surface contact with the end portion 33 of the substrate-side surface 32 of the imaging device 3.

According to the imaging module 1 according to the embodiment of the present invention, the substrate 2 is provided with the recess 24, and the substrate-side surface 32 of the imaging device 3 and the mounting surface 22 surrounding the recess 24 of the substrate 2 are in surface contact, Since the substrate 2 and the image sensor 3 are joined by the solder balls 4 located in the recess 24, the substrate 2 and the image sensor 3 are surely parallel. In particular, even if there is a variation in the size of the solder balls 4 before fusion bonding, the substrate 2 and the image sensor 3 can be bonded in parallel without being affected by this. Thus, by incorporating the optical system with the mounting surface 21 of the substrate 2 as a reference, the optical system is appropriately set even for the image pickup device 3 parallel to the substrate 2, and the optical axis can be easily adjusted. It becomes like this.
Since a structure for making the substrate 2 and the image sensor 3 parallel is also provided on the substrate 2 side, a simple apparatus configuration and low cost can be achieved without newly using components.

In addition, referring to the enlarged view of FIG. 2, the depth H of the recess 24 is preferably 80% or more and 97% or less of the diameter D of the solder ball 4 before fusion bonding.
The solder ball 4 shrinks by about 10 to 20% in the height direction by fusion bonding, but if the depth H of the recess 24 is smaller than 80% with respect to the diameter D of the solder ball 4 before fusion bonding, the shrinkage factor is considered. Even so, the solder ball 4 is relatively larger than the recess, and the end 33 of the substrate side surface 32 of the image sensor 3 floats from the mounting surface 22 surrounding the recess 24 of the substrate 2, and the image sensor 3 tilts. There is a risk that. In order to prevent this, if the end 33 of the substrate side surface 32 of the image sensor 3 is pressed until it contacts the mounting surface 22 surrounding the recess 24 of the substrate 2, the solder balls 4 spread in the width direction of the recess 24. Adjacent solder balls may come into contact with each other. On the other hand, if the depth H of the recess 24 is larger than 97% with respect to the diameter D of the solder ball 4 before fusion bonding, the contact area between the solder ball 4 and the image sensor 3 may be too small and the bonding strength may be reduced. . Therefore, by setting the depth H of the concave portion 24 within the above range, the mounting surface 22 surrounding the concave portion 24 of the substrate 2 and the end portion 33 of the substrate-side surface 32 of the image sensor 3 are surely brought into contact with each other after fusion bonding. In addition, the distance between adjacent solder balls can be kept constant, and the bonding strength between the substrate 2 and the image sensor 3 can be kept.

3 to 6 are plan views of the imaging module 1 as seen from the imaging element 3 side.
The shape of the recess 24 is not particularly limited, but when viewed from the mounting surface 21 side, a square shape as shown in FIG. 3 or 5, a cross shape as shown in FIG. 4, and FIGS. 6 (a) and 6 (b). A circular shape as shown is used.
In the first example shown in FIG. 3, the recess 24 is formed in a square shape that is slightly smaller than the image sensor 3 when viewed from the mounting surface 21 side. On the bottom surface of the recess 24, the solder balls 4 are arranged in a grid. The mounting surface 22 surrounding the concave portion 24 of the substrate 2 is in contact with the end portion 33 of the substrate side surface 32 of the image pickup device 3 over the entire circumference. That is, among the end portions 33 of the substrate-side surface 32 of the image sensor 3, the opposed end portions 33a and 33c are in surface contact with the mounting surface 22 of the substrate 2, and the opposed end portions 33b and 33d are in contact with each other. Each is in surface contact with the mounting surface 22 of the substrate 2, and is in surface contact with the mounting surface 22 of the substrate 2 over the entire circumference of the end portion 33 of the image sensor 3. As described above, when the end portion 33 of the substrate 2 is in surface contact with the mounting surface 22 of the substrate 2 over the entire circumference of the recess 24, the contact area between the imaging element 3 and the substrate 2 can be increased. Parallelism can be kept stable.

  In the second example shown in FIG. 4, the recess 24 is formed in a cross shape when viewed from the mounting surface 21 side. Of the mounting surface that surrounds the recess 24 of the substrate 2, the mounting surface 22 that protrudes toward the center of the cross is in surface contact with the end portions 33 e to 33 h of the image sensor 3. There are four parts in surface contact, the end 33e and the end 33g of the image sensor 3 are located facing each other, and the end 33f and the end 33h are located facing each other. On the bottom surface of the recess 24, the solder balls 4 are arranged in a grid. Further, a gap is provided between the end portion 34 of the image sensor 3 that is not in contact with the mounting surface 22 of the substrate 2 and the mounting surface 21 surrounding the recess 24 of the substrate 2, and an opening that communicates the recess 24 with the outside. A portion 40 is formed.

  In this way, the recesses 24 are formed in a cross shape, and the end portions 33e to 33h located at the four corners of the image sensor 3 and the mounting surface 22 surrounding the recess 24 of the substrate 2 are brought into surface contact with each other. 3 can be parallel. Furthermore, by forming the opening 40 that communicates the concave portion 24 of the substrate 2 with the outside, when the solder ball 4 melted at the time of reflow is cured, the heat dissipation effect can be enhanced and the curing can be promoted. In addition, even when the imaging module 1 is incorporated in the imaging apparatus, the imaging module 1 has an excellent heat dissipation effect, and when the imaging element 3 is driven to generate heat, heat can be radiated from the opening 40. Further, since the entire periphery of the end of the image sensor 3 is not in surface contact with the mounting surface 21 of the substrate 2, the package of the image sensor 3 can be reduced in size. Furthermore, the mounting area of the solder balls 4 can be effectively taken with respect to the substrate-side surface 32 of the image sensor 3.

  In the third example shown in FIG. 5, the recess 24 is formed in a rectangular shape when viewed from the mounting surface 21 side. Of the mounting surface 22 surrounding the recess 24 of the substrate 2, two sides facing each other across the recess 24 are in surface contact with the end 33 i and the end 33 j of the image sensor 3. There are two parts that make surface contact. On the bottom surface of the recess 24, the solder balls 4 are arranged in a grid. Further, similarly to the second example, a gap is provided between the end portion 34 of the imaging element 3 that is not in contact with the mounting surface 22 of the substrate 2 and the mounting surface 21 surrounding the recess 24 of the substrate 2, so that the recess 24 An opening 40 that communicates with the outside is formed.

In this way, the concave portion 24 is formed in a rectangular shape, and the two opposite end portions 33i and 33j of the image sensor 3 are brought into contact with the mounting surface 22 surrounding the concave portion 24 of the substrate 2, respectively. The board | substrate 2 and the image pick-up element 3 can be made parallel. Furthermore, by forming the opening 40 that allows the recess 24 of the substrate 2 to communicate with the outside, as in the second example, it is possible to enhance the heat dissipation effect during reflow and promote curing, and the imaging module 1 can be used as an imaging device. Even in the state where it is incorporated in, it has an excellent heat dissipation effect. In addition, the package of the image pickup device 3 can be reduced in size, and the mounting area of the solder balls 4 can be effectively taken with respect to the substrate-side surface 32 of the image pickup device 3.
When comparing the second example and the third example having the opening 40, the heat dissipation effect is higher in the second example, and the parallel stability of the substrate 2 and the imaging element 3 is higher in the third example. .

The fourth example shown in FIG. 6A is an example in which the image sensor package can be further reduced, and the fifth example shown in FIG. 6B is an example in which the mounting area of the image sensor package can be more effectively secured.
In the fourth example and the fifth example, the recess 24 is formed in a circular shape when viewed from the mounting surface 21. On the other hand, the image sensor 3 is formed in a square shape. Of the surface of the image pickup device 3 on the substrate side, the four end portions 33k to 33n located at the corners are in surface contact with the mounting surface 22 surrounding the recess 24 of the substrate 2, respectively. There are four parts that are in surface contact, the end 33k and the end 33m of the image sensor 3 are located facing each other, and the end 33l and the end 33n are located facing each other. On the bottom surface of the recess 24, the solder balls 4 are arranged in a grid. Further, a gap is provided between the end portion 34 of the image sensor 3 that is not in contact with the mounting surface 22 of the substrate 2 and the mounting surface 21 surrounding the recess 24 of the substrate 2, and an opening that communicates the recess 24 with the outside. A portion 40 is formed. There are four openings 40.

  In this manner, the recesses 24 are formed in a circular shape, and the end portions 33k to 33n positioned at the four corners of the image sensor 3 and the mounting surface 22 surrounding the recess 24 of the substrate 2 are brought into surface contact with each other. 3 can be parallel. Furthermore, by forming the opening 40 that communicates the concave portion 24 of the substrate 2 with the outside, when the solder ball 4 melted at the time of reflow is cured, the heat dissipation effect can be enhanced and the curing can be promoted. In addition, even when the imaging module 1 is incorporated in the imaging apparatus, the imaging module 1 has an excellent heat dissipation effect, and when the imaging element 3 is driven to generate heat, heat can be radiated from the opening 40. Further, since the entire periphery of the end of the image sensor 3 is not in surface contact with the mounting surface 21 of the substrate 2, the package of the image sensor 3 can be reduced in size. Furthermore, the mounting area of the solder balls 4 can be effectively taken with respect to the substrate-side surface 32 of the image sensor 3.

  In particular, in the above-described fourth example, the concave portion 24 is formed in a circular shape, and the end portions 33k to 33n positioned at the corners of the rectangular imaging element 3 are in surface contact with the mounting surface 22 of the substrate 2. As compared with the first example, the image pickup device package can be further reduced in size. In the fifth example, the concave portion 24 is circular, and the end portions 33k to 33n located at the corners of the rectangular imaging element 3 are brought into surface contact with the mounting surface 22 of the substrate 2, and the concave portion 24 and the imaging element are also in contact with each other. Since the area of 3 is larger than that of the fourth example, the mounting area of the solder balls 4 can be made more effective than that of the first example.

FIG. 7 is a side cross-sectional view of an imaging module having an optical system. As shown in the figure, the imaging module 1 may be provided with an optical system holding unit 5 that holds an optical system 6 on a substrate 2 on which the imaging device 3 is mounted via a solder ball 4. In this case, the optical system holding unit 5 is provided on the mounting surface 21 around the recess 24 of the substrate 2.
The optical system 6 is configured by combining one or more optical elements such as an optical lens, an optical filter, or a prism. The optical system holding part 5 is formed in a cylindrical shape and holds the optical system 6 on the inner peripheral surface.

In this way, by attaching the optical system holding unit 5 holding the optical system 6 to the mounting surface 21 around the recess 24 of the substrate 2, the reference surface of the optical system 6 orthogonal to the optical axis is used as the mounting surface 21 of the substrate 2. It is possible to make the optical axis of the optical system 6 orthogonal to the image pickup device 3 by making the image pickup device 3 parallel to the mounting surface 21 of the substrate 2.
Note that it is preferable to configure an imaging apparatus including the imaging module 1 shown in at least one of FIGS. The imaging device is, for example, a digital still camera, a portable camera, a vehicle-mounted camera, a surveillance camera, an imaging means of an image inspection device, or the like.

Next, a manufacturing method of the imaging module 1 according to the embodiment of the present invention will be described below.
First, the recess 24 is formed in the mounting surface 21 of the substrate 2. In the case of the multilayer substrate 2 as shown in FIG. 8, preferably, through holes are formed in advance in the insulating layer 20a corresponding to the recesses 24 among the layers constituting the substrate 2, and the insulating layer in which the through holes are formed. 20a, a conductive layer 20b, another insulating layer 20c, another conductive layer 20d, and another insulating layer 20e are sequentially stacked. At this time, the mounting surface 21 exposed on the surface and the opposite surface 23 are provided with an insulating layer or provided with an insulating film. Further, when the layer corresponding to the bottom surface of the recess 24 is a conductive layer, an insulating film (not shown) is provided on the surface. In addition, although it is set as the structure which provided the through-hole only in one layer in drawing, it is good to set the number of layers which provide a through-hole according to the depth of the recessed part 24. FIG. By manufacturing the substrate 2 having the recess 24 in this manner, the recess 24 can be easily formed. Preferably, the depth of the recess 24 is 80% or more and 97% or less of the diameter of the solder ball 4 before fusion bonding.

On the image sensor 3, solder balls 4 having a diameter larger than the depth of the recess 24 are arranged in a grid. Preferably, the solder ball 4 is formed so that its diameter is larger than the depth of the recess 24 by a length of 3% to 25%. The solder balls 4 are formed on electrode pads or extraction electrodes provided on the image sensor 3.
Next, the substrate 2 and the image sensor 3 are faced to be aligned and fixed so that the solder ball 4 is positioned in the recess 24 of the substrate 2. At this time, the solder ball 4 is fixed to a position where the solder ball 4 contacts the electrode pad or the extraction electrode of the substrate 2.

Then, the substrate 2 and the image sensor 3 facing each other with the solder ball 4 interposed therebetween are introduced into a reflow furnace, and this is heated to a temperature at which the solder ball 4 melts. During heating, a pressure toward the solder ball 4 may be applied to the substrate 2 or the image sensor 3. The solder ball 4 is melted and fused to the substrate-side surface 32 of the image pickup device 3 and contracts in the height direction, but the mounting surface 22 that surrounds the recess 24 of the substrate 2 and the substrate-side surface 32 of the image pickup device 3. When the end portion 33 abuts, the solder ball 4 will not shrink any further.
After the solder ball 4 is melted, the substrate 2, the image sensor 3 and the solder ball 4 are cooled, and the solder ball 4 is cured. When pressure is applied to the substrate 2 or the image sensor 3, the pressure is released when the solder ball 4 is cured. When the solder balls 4 are cured, the mounting surface 22 of the substrate 2 and the substrate-side surface 32 of the image sensor 3 are kept in surface contact with each other, and the substrate 2 and the image sensor 3 are joined by the solder balls 4 in the recesses 24. The imaging module 1 is manufactured.

  According to the method for manufacturing the image pickup module 1 according to the present invention, the substrate 2 and the image pickup device 3 are made to face each other so that the solder balls 4 disposed on the image pickup device 3 are located in the recesses 24 formed on the substrate 2. After that, the solder ball 4 is heated and melted, and the substrate 2 and the image pickup device 3 are joined in a state where the end portion 33 of the substrate side surface 32 of the image pickup device 3 and the mounting surface 22 surrounding the concave portion 24 of the substrate 2 are in surface contact. Therefore, the substrate 2 and the image sensor 3 can be joined in a parallel state. In particular, even if there is a variation in the size of the solder balls 4 before fusion bonding, the substrate 2 and the image sensor 3 can be bonded in parallel without being affected by this. Thus, by incorporating the optical system with the mounting surface 21 of the substrate 2 as a reference, the optical system is appropriately set even for the image pickup device 3 parallel to the substrate 2, and the optical axis can be easily adjusted. It becomes like this. In addition, since the structure for making the image pickup device 2 and the substrate 3 parallel is provided on the substrate 2 side, a simple apparatus configuration and low cost can be achieved without newly using components.

DESCRIPTION OF SYMBOLS 1 Imaging module 2 Board | substrate 21 Mounting surface 22 Mounting surface 24 surrounding a recessed part Recessed part 3 Image pick-up element 31 Light receiving surface 32 Board | substrate side surface 33, 33a-33j End part 4 Solder ball 5 Optical system holding | maintenance part 6 Optical system 40 Opening part

Claims (9)

A substrate in which a recess is formed on the mounting surface, and an external connection electrode is provided in the recess;
An image sensor mounted on the mounting surface of the substrate;
A solder ball for joining the substrate and the image sensor;
In a state where the substrate and the image sensor are joined via the solder ball, a pair of end portions facing each other with at least the recess between the substrate-side surfaces of the image sensor surround the recess of the substrate. An imaging module, wherein the imaging module is in surface contact with the mounting surface.   The imaging module according to claim 1, wherein a depth of the concave portion is 80% or more and 97% or less of a diameter of the solder ball before the substrate and the imaging device are joined.   3. The imaging module according to claim 1, wherein the mounting surface surrounding the concave portion of the substrate and the end portion of the substrate-side surface of the imaging element are in surface contact over the entire circumference of the concave portion. .   An opening is provided between the end of the imaging element that is not in surface contact with the mounting surface of the substrate and the mounting surface that surrounds the recess of the substrate, and communicates the recess with the outside of the imaging module. The imaging module according to claim 1, wherein a part is formed. An optical system holder fixed to the mounting surface of the substrate;
The imaging module according to claim 1, further comprising an optical system held by the optical system holding unit.   An imaging apparatus comprising the imaging module according to claim 1. In an imaging module manufacturing method for manufacturing an imaging module by joining a substrate and an imaging element mounted on a mounting surface of the substrate with a solder ball,
A concave portion is formed on the mounting surface of the substrate, and a plurality of the solder balls having a diameter larger than the depth of the concave portion are disposed on the substrate side surface of the imaging element,
Making the substrate and the imaging element face each other so that the solder ball is located in the recess;
The solder ball is heated and melted, and at least a pair of opposite end portions of the substrate-side surface of the imaging element facing the concave portion are brought into surface contact with the mounting surface surrounding the concave portion of the substrate. Bonding the substrate and the imaging device by:
And a step of curing the solder ball. An imaging module manufacturing method comprising:   The method of manufacturing an imaging module according to claim 7, wherein the solder ball disposed on the imaging element has a diameter that is greater than or equal to 3% and less than or equal to 25% than a depth of the concave portion of the substrate. The substrate is a multilayer substrate;
A through hole is previously formed in a layer corresponding to the concave portion among the layers constituting the substrate, and the concave portion is formed by stacking a plurality of layers including the layer in which the through hole is formed. The method for manufacturing an imaging module according to claim 7, further comprising a step of manufacturing the imaging module.

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