Field of the Invention
The present technique relates to mounting an electronic component.
Description of the Related Art
An electronic component is manufactured by primarily mounting an electronic device on a mounting member and by secondarily mounting the electronic component on a wiring member. Japanese Patent Laid-Open No. 2013-243339 describes an electronic component in which an electronic device is mounted on a mounting member and in which the electronic device is sealed in an airtight manner with a lid. The electronic component is secondarily mounted by bonding external terminals (connecting portions) provided on a back side of the electronic component to a wiring member by reflow soldering.
As in Japanese Patent Laid-Open No. 2013-243339, in an electronic component having an air tight space therein, there are cases in which, when performing reflow soldering, the space inside is expanded by heat and a back side of the electronic component is expanded towards a wiring member. In such a case, the distances between terminals provided on the back side of the electronic component and terminals of the wiring member may differ in each terminal, and the reliability of the solder bonding may be compromised.
Accordingly, the present technique provides an electronic component and a method for manufacturing an electronic module, which improves the connection of the connecting portions.
The present technique provides an electronic component including an electronic device and a container accommodating the electronic device. The container includes a base portion including a first surface on which the electronic device is mounted and a second surface that is on an opposite side of the first surface, an opposing portion that opposes the electronic device, a frame portion that surrounds the space between the base portion and the opposing portion, and a plurality of connecting portions that are disposed on the second surface and disposed in at least an orthographic projection area of the electronic device, the plurality of connecting portions being bonded to a wiring member. In the orthographic projection area of the electronic device, a thickness of the base portion in a central area is smaller than a thickness of the base portion in a peripheral area such that the second surface forms a concave surface.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, a mode for carrying out the present technique will be described with reference to the drawings. Note that in the following description and in the drawings, components that are common throughout the plurality of drawings are attached with common reference numerals. Accordingly, common components will be described while referring to the plurality of drawings, and description of the components attached with common reference numerals will be omitted as appropriate.
Referring to the figures, the mode for carrying out the present technique will be described.
Referring to
The electronic component 100 includes an electronic device 110 and a container 1111 that accommodates the electronic device 110. A typical electronic device 110 is a semiconductor device; however, the electronic device 110 is not limited to a semiconductor device. The electronic device 110 may be an imaging device, a display device, or an MEMS device. As illustrated in
The container 1111 includes a base portion 121, an opposing portion 123, and a frame portion 122. The base portion 121 includes a mounting surface 160 on which the electronic device 110 is mounted and a connection surface 170 located on the other side of the mounting surface 160. The back side of the electronic device 110 opposes the mounting surface 160 with a bonding material (not shown) in between. An orthographic projection area 150 of the electronic device 110 in the mounting surface 160 is a mounting area 161. An outer edge of the mounting surface 160 is defined by the frame portion 122. The mounting surface 160 may include a peripheral area 162 (see
The container 1111 may include an internal connecting portion group 180 including a plurality of connecting portions 181, 182, 183, 184, and 185 on the space 140 side. Each connecting portion of the internal connecting portion group 180 is connected to the corresponding electrode 112 serving as a bonding pad of the electronic device 110 by wire bonding connection or by flip chip connection. When wire bonding connection is performed, each connecting portion of the internal connecting portion group 180 may be positioned outside the orthographic projection area 150 of the electronic device 110. In the present example, the internal connecting portion group 180 is disposed from the mounting surface 160 to a step portion of the stepped frame portion 122. When flip chip connection is performed, each connecting portion of the internal connecting portion group 180 may be positioned inside the orthographic projection area 150 of the electronic device 110. In such a case, the internal connecting portion group 180 may be provided in the base portion 121.
The container 1111 may include an external connecting portion group 190 including a plurality of connecting portions 191, 192, 193, 194, and 195 on the side opposite the space 140 side. Each connecting portion of the external connecting portion group 190 is electrically connected to the corresponding connecting portion of the internal connecting portion group 180. For example, the connecting portion 191 is electrically connected to the connecting portion 181, the connecting portion 182 to the connecting portion 192, the connecting portion 193 to the connecting portion 183, the connecting portion 184 to the connecting portion 194, and the connecting portion 185 to the connecting portion 195. The plurality of connecting portions 191, 192, and 195 are positioned on the connection surface 170 side and inside the orthographic projection area 150 of the electronic device 110, and are soldered to a wiring member that is provided separately from the electronic component 100. The wiring member is a circuit substrate, such as a printed circuit board using a flexible substrate or a rigid substrate.
The connecting portions 191 and 195 are positioned in a central area 151 of the orthographic projection area 150, and the connecting portions 192 are positioned in a peripheral area 152 of the orthographic projection area 150. Note that the central area 151 can be defined as an area corresponding to the functional area 111 of the electronic device 110, and the peripheral area 152 can be defined as an area other than the functional area 111 of the electronic device 110; however, the central area 151 and the peripheral area 152 are not limited to the above definitions. In another definition, the peripheral area 152 may be defined as a portion ranging from the edge of the electronic device 110 to a portion that is one fourth of the dimension of the electronic device 110, and the central area 151 may be defined as the area surrounded by the peripheral area 152. The container 1111 may include the connecting portions 193 and 194 that are positioned on the connection surface 170 side and in an outer area 153 that is outside the orthographic projection area 150 of the electronic device 110. Note that the connecting portions 191 to 195 may be connecting portions that contribute to the electrical connection; however, the connecting portions 191 to 195 may not contribute to the electrical connection and may be connecting portions for reinforcing mechanical connection or may be connecting portions for releasing heat. For example, the connecting portions 194 and 195 may have larger areas than those of the other connecting portions 191, 192, and 193 and may bear the role of mechanical and thermal connection. As the form of the connecting portions 191 to 195, a land grid array (LGA), a pin grid array (PGA), a ball grid array (BGA), a quad flat no-lead package (QFN), or a quad flat package (QFP) may be employed.
In the present example, the base portion 121, the frame portion 122, the internal connecting portion group 180, and the external connecting portion group 190 constitute a mounting member 120. The frame portion 122 may be, in the mounting member 120, a portion that is positioned in the outer area 153 of the electronic device 110. The opposing portion 123 may be, in a lid member 130 that is adhered to the frame portion 122 of the mounting member 120, a portion that is positioned in the orthographic projection area 150 of the electronic device 110. The lid member 130 includes a peripheral portion 124 at a portion around the opposing portion 123, and the peripheral portion 124 is bonded to the frame portion 122. Instead of providing the base portion 121 and the frame portion 122 in the mounting member 120, a lid member including the opposing portion 123 and the frame portion 122 may be adhered to a mounting member that includes the base portion 121. In the present example, the base portion 121 and the frame portion 122 of the mounting member 120 are formed in an integrated manner with the same type of material; however, the base portion 121 and the frame portion 122 may be formed of different types of materials and may be bonded to each other. The base portion 121 is formed of an insulating material, such as resin or ceramic. The frame portion 122 is formed of resin, ceramic, metal, or the like. While the mounting member 120 may be made of ceramic, it is desirable that the mounting member 120 is made of plastic with a lower rigidity. Regarding the mounting member 120, the base portion 121 and the frame portion 122 of the mounting member 120 may be formed in an integrated manner by resin molding.
Note that in a case in which the connection surface 170 is a flat surface, when the space 140 expands upon an increase in temperature of the electronic component 100, there may be cases in which the connection surface 170 is deformed to have a convex surface. Such an increase in temperature occurs during, for example, heat treating, such as reflow soldering performed when an electronic module is manufactured by mounting the electronic component 100 on a wiring member. Furthermore, the increase in temperature may occur due to heat generation of the electronic device 110 while a piece of electronic equipment on which the electronic component 100 is mounted is being used. Increase in temperature during fabrication may cause a bonding defect, such as a short circuit or an open circuit, while performing soldering and may reduce the yield. Increase in temperature during use may cause deterioration in the solder joints and may lower the reliability.
Conversely, in the electronic component 100 according to the present exemplary embodiment, the connection surface 170 has a concave surface that is recessed towards the mounting surface 160 side. By having the connection surface 170 have a concave surface in advance, when the temperature of the electronic component 100 increases, compared with a case in which the connection surface 170 has a flat surface in advance, the flatness of the connection surface 170 can be increased. As a result, reliability in the solder joint can be improved when performing heat treating during fabrication and when the temperature increases during use. Note that when the rigidities of the container 1111 and the wiring member are extremely high, for example, the deformation of the connection surface 170 upon increase in temperature may not be so large. In such a case as well, having the connection surface 170 have a concave surface is advantageous in reducing the stress caused on the electronic component 100.
A form of the connection surface 170 will be described in detail next. Regarding the shape of the base portion 121,
The mounting surface 160 may be flatter than the connection surface 170. The mounting surface 160 may have a flat surface or may have a concave surface. The mounting surface 160 may have a concave surface that is flatter than the concave surface of the connection surface 170.
In the orthographic projection area 150 of the electronic device 110, the thickness of the electronic component 100 in the central area 151 may be smaller than the thickness of the electronic component 100 in the peripheral area 152. In other words, a thickness Dc of the electronic component 100 in the central area 151 may be smaller than a thickness Dp of the electronic component 100 in the peripheral area 152 (Dc<Dp). In a case in which the electronic device 110 is an imaging device, desirably, the surface of the electronic device 110 on the opposing portion 123 side has a flat shape or a concaved shape. By so doing, influence of field curvature, which is one of the aberrations of a lens optical system, can be limited.
Conversely,
Note that, optimally, the curved shape of the electronic device 110 extends along the curved surface of the field curvature of the optical system; however, a certain degree of non-coincidence with the curved surface of the field curvature can be permitted as long as the curved shape of the electronic device 110 has a concave shape. However, if the curved shape of the electronic device 110 is a convex shape, the peripheral portion will become out of focus and, accordingly, it is unfavorable with respect to image quality.
For comparison, a case in which the entire connection surface 170 is flat is illustrated in
Furthermore, for comparison, a case in which the entire orthographic projection area 150 of the connection surface 170 is flat and is recessed with respect to the outer area 153 is illustrated in
Conversely, if the connection surface 170 in the orthographic projection area 150 forms a concave surface, the electronic component 100 expands and the connection surface 170 becomes almost flat upon heating such that a favorable bond can be formed.
As described above, the present technique is capable of improving the connection reliability of the connecting portions. The present technique is not limited to the matters described above and may be appropriately modified within the scope of the technical idea.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2015-120405, filed Jun. 15, 2015, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2015-120405 | Jun 2015 | JP | national |