JP3748799B2 - Electronic component package and mounting method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component package incorporating a semiconductor and a mounting method thereof, and more particularly to an electronic component package including a component having low heat resistance.
[0002]
[Prior art]
In recent years, along with the miniaturization of various electronic devices, electronic components mounted thereon have also been miniaturized and chip-ized. Conventionally, in mounting these electronic components on a circuit board, a surface mounting method in which a reflow furnace is used for soldering is common. Among such electronic components, for example, electronic components in which a semiconductor and a lens are integrated, such as a CCD with a lens and a CMOS sensor with a lens, are widely used for industrial, medical, and consumer use. It has become. In addition, these lenses employ aspherical plastic lenses with good performance even with a single lens in order to reduce the price. An example of such a conventional electronic component package will be described with reference to the drawings. 4 is a perspective view of a conventional electronic component package, and FIG. 5 is a longitudinal sectional view of FIG. 6 is a partially exploded perspective view of another conventional electronic component package, and FIG. 7 is a partially exploded longitudinal sectional view of the electronic component package of FIG.
[0003]
First, the configuration of the electronic component package of FIGS. 4 and 5 will be described. In FIG. 4, reference numeral 51 denotes an electronic component package that houses a CMOS sensor, which is an electronic component, as a semiconductor, and is configured by joining a wiring substrate 52 and a case 53, which is a resin molded product. The wiring substrate 52 is made of resin, ceramic, or the like, and a wiring pattern (not shown) is formed on the upper and lower surfaces of the substrate 52. 54 is a connection terminal that is extended to the wiring pattern on the back side through a half-through-hole portion formed on the side surface of the substrate 52 so that a part of the wiring pattern on the surface of the substrate 52 is connected to the wiring pattern on the back surface. is there. The electronic component package 51 is bonded to the electrode pattern of the circuit board that is the motherboard of the electronic device via the connection terminal 54.
[0004]
Reference numeral 55 denotes an IC as a main component constituting the CMOS sensor, which is bonded to the wiring pattern at the center of the upper surface of the substrate 52 by die bonding. Reference numeral 56 denotes a wire, which connects each electrode of the IC 55 and a corresponding wiring pattern by wire bonding. Reference numeral 57 denotes a double-sided aspheric plastic lens that is generally used for cost reduction, and is fixed to the lens barrel 53a at the step portion of the lens hole 53b formed in the center of the case 53. Narrowed by 58 apertures. A concave portion 53 c for accommodating the IC 55 is formed on the lower surface of the case 53.
[0005]
Next, the configuration of the electronic component package of FIGS. 6 and 7 will be described. 6 and 7, reference numeral 61 denotes an electronic component package for accommodating a CMOS sensor, which is an electronic component as a semiconductor, and is formed by fitting 62 substrate blocks and 63 case blocks. Reference numeral 64 denotes a wiring board of the substrate block 62 made of resin, ceramic or the like, and 65 ICs are housed in the recesses 64b formed inside the substrate block 62. Reference numeral 66 denotes a glass plate that is joined to a frame portion 64a formed to protrude from the upper surface of the substrate 64 and covers the concave portion 64b. The case block 63 is obtained by assembling the lens 57 in 67 cases. Other configurations are the same as those of the electronic component package 51 described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.
[0006]
[Problems to be solved by the invention]
When soldering a conventional one-chip electronic component onto a circuit board of an electronic device, a method of soldering using a reflow furnace generally has good productivity. However, in the case of electronic parts including parts that are not heat-resistant enough to withstand a reflow furnace, such as plastic lenses, it is necessary to heat only the terminal part using manual soldering or a light beam. It has become. In addition, the case block 63 and the substrate block 62 are manufactured separately in advance. First, only the substrate block 62 that is not concerned with heat resistance is first soldered using a reflow furnace, and then the case block 63 is processed. In the method of joining the substrate block 62 to the substrate block 62, the frame portion 64a is provided on the substrate block 62, and extra components such as the glass plate 66 are increased. Therefore, the cost of the electronic component itself is increased, and the man-hours and equipment in the mounting process are excessive for general electronic components.
[0007]
The above invention has been made to solve such a conventional problem, and its purpose is to store electronic parts including parts having low heat resistance that cannot withstand a reflow furnace, and to perform soldering by a reflow furnace. It is to provide an electronic component package that can be used.
[0008]
[Means for Solving the Problems]
Means of the present invention for achieving the above-mentioned object comprises an electronic component package comprising a wiring board having an external connection terminal and a wiring pattern, and a case fixed to the wiring board, and incorporating a semiconductor as a main component. A sealed cavity is provided in the case so as to communicate with the outside only through a vent hole, and a water-absorbing polymer is built in the cavity.
[0009]
Further, a lens hole and the vent hole are opened in the upper surface of the case, and a plastic lens is fixed in the lens hole.
[0010]
The cavity is formed so as to surround the periphery of the lens.
[0011]
In addition, an adhesive tape is attached to the upper surface of the case so as to close the vent hole.
[0012]
According to another aspect of the present invention, there is provided a method for mounting an electronic component package according to claim 4, wherein the water absorbing polymer is previously absorbed and then the vent hole is closed with an adhesive tape. And solder reflow.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of an electronic component package according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the electronic component package, and FIG. 3 is a perspective view showing a method of mounting the electronic component package.
[0014]
First, the configuration of the electronic component package according to the embodiment of the present invention will be described. 1 and 2, reference numeral 1 denotes an electronic component package. Reference numeral 2 denotes a substrate made of resin, ceramic or the like, and a wiring pattern is formed on the upper and lower surfaces of the substrate 2. Reference numeral 3 denotes a connection terminal formed by extending a part of the wiring pattern from the upper surface of the substrate 2 to the back surface side via a half through-hole portion on the side surface. Reference numeral 4 denotes a semiconductor IC which is a main electronic component built in the electronic component package 1, and a CCD or CMOS sensor as a solid-state imaging device is generally used. Reference numeral 5 denotes a wire for bonding the electrode of the IC 4 and the wiring pattern of the substrate 2 by wire bonding.
[0015]
Reference numeral 6 denotes a case made of a resin molded product joined on the substrate 2, and has a lens hole 6a which is a through hole in the center. A cavity 6b is formed in the case 6 so as to surround the periphery of the lens hole 6a. Reference numeral 8 denotes a lid made of a resin molded product, which is joined to the case 6 to make the cavity 6b a sealed space. The lid 8 is formed with a lens hole 8a and a vent hole 8b for communicating the cavity 6b with the outside air. Reference numeral 7 denotes a plastic lens having both aspheric surfaces, and is sandwiched by a lid 8 together with an aperture 10 in a step portion in the lens hole 6a. Reference numeral 9 denotes a water-absorbing polymer accommodated in the cavity 6b.
[0016]
Next, a method for mounting the electronic component package 1 on the circuit board of the electronic device will be described. In FIG. 3, 11 is an adhesive tape. First, water is sufficiently supplied to the water-absorbing polymer 9 from the vent hole 8b, and the adhesive tape 11 is stuck on the upper surface of the case 6 so as to close the vent hole 8b and the lens hole 6a. In this way, the electronic component package 1 is mounted on a circuit board in the same manner as a general electronic component by a chip mounter or the like, and soldered by a reflow furnace. In this case, the water is boiled and vaporized by the heat during reflow, the pressure in the cavity 6b is increased, and the adhesive tape 11 is partially peeled and goes out. After the solder reflow, the adhesive tape 11 is removed to complete the mounting.
[0017]
Next, effects of the semiconductor package according to the present embodiment will be described. According to the mounting method described above, since the cavity 6b is sealed with the adhesive tape 11, evaporation can be prevented and sufficient moisture can be held during standby before soldering. In the reflow furnace, while the moisture is present, the temperature rise of the case 6 near the cavity 6b is suppressed to around 100 ° C., which is the boiling point of water, so that the temperature rise of the nearby lens 7 can also be suppressed. Therefore, the lens 7 can withstand soldering by a reflow furnace. Moreover, since the lens hole 6a is covered with the adhesive tape 11, it is possible to prevent the lens from being contaminated by gas or dust during operation.
[0018]
In the above embodiment, the diaphragm 10 of the lens 7 is an independent component. However, it can be integrally formed with the lid 8 to reduce the number of components. Moreover, although the adhesive tape 11 is covered also in the lens hole 6a, when the contamination of the lens can be prevented by another method, the adhesive tape 11 may only block the ventilation hole 8b. Further, since the water-absorbing polymer 9 can be retained in a large amount even if it is a liquid other than water, for example, when a liquid such as a fluorine-based inert liquid is used, the boiling point can be selected in a wide range. Therefore, it is effective if it is applied to a component in which the influence on the electronic component is concerned with water. Of course, the parts having low heat resistance are not limited to the plastic lens described above. As described above, if the electronic component package of the present invention is applied to an electronic component including a member having low heat resistance, it can be made into an electronic component that can be soldered in the same manner as a general electronic component. Improvement can be achieved.
[0019]
【The invention's effect】
As described above, according to the present invention, in an electronic component package including a semiconductor mounted on a substrate and a case to which the substrate is fixed, a sealed cavity that communicates with the outside only through a vent hole in the case. Since the water-absorbing polymer is built in the cavity, when soldering to the circuit board, the water-absorbing polymer is supplied in advance and sealed with an adhesive tape to include parts with low heat resistance. However, it has become possible to mount solder with good productivity by using a reflow furnace for electronic components.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electronic component package according to an embodiment of the present invention.
2 is a longitudinal sectional view of the electronic component package of FIG. 1. FIG.
3 is a perspective view showing a method for solder mounting the electronic component of FIG. 1; FIG.
FIG. 4 is a perspective view of a conventional electronic component package.
FIG. 5 is a longitudinal sectional view of a conventional electronic component package.
FIG. 6 is a partially exploded perspective view of another conventional electronic component package.
FIG. 7 is a partially exploded longitudinal sectional view of a conventional electronic component package.
[Explanation of symbols]
1 Electronic Component Package 2 Wiring Board 3 Connection Terminal 4 IC
6 Case 6a Lens hole 6b Cavity 6c Vent hole 7 Lens 8 Water-absorbing polymer 9 Adhesive tape

Claims (5)

  An electronic component package comprising a wiring board having an external connection terminal and a wiring pattern, and a case fixed to the wiring board. An electronic component package comprising a sealed cavity and a water-absorbing polymer incorporated in the cavity.   2. The electronic component package according to claim 1, wherein a lens hole and a ventilation hole are opened in the upper surface of the case, and a plastic lens is fixed in the lens hole. 3. The electronic component package according to claim 2, wherein the cavity is formed so as to surround the periphery of the lens. The electronic component package according to claim 2 , wherein an adhesive tape is attached to an upper surface of the case so as to close the vent hole. 5. The method of mounting an electronic component package according to claim 4 , wherein after the water absorbing polymer absorbs water in advance, the vent hole is closed with an adhesive tape and then solder reflow is performed.

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