JP6301738B2 - Electronic device mounting package and electronic device - Google Patents

Description

The present invention relates to an electronic device mounting package and an electronic device in which an electronic device, for example, a charge coupled device (CCD) type or a complementary metal oxide semiconductor (CMOS) type imaging device is mounted.

  2. Description of the Related Art Conventionally, an electronic device in which an image sensor such as a CCD type or a CMOS type is mounted on a package is known. As such an electronic device, an electronic device is mounted on a package, the package is mounted on a flexible substrate, and the electronic device is electrically connected to a printed circuit board or the like via a connector.

JP2006-339293

  Due to the recent increase in demand for high-definition images and moving images, the load on the electronic elements is increasing, and the heat generated from the electronic elements is large. If the heat generated from the electronic element is not sufficiently dissipated to the outside, the electrical characteristics of the signal output from the electronic element may be degraded by heat, or the electronic element may be peeled off from the package by the heat and normal imaging cannot be performed. The

An electronic element mounting package according to an aspect of the present invention includes a metal plate serving as a base, an insulating base having an insulator, and the metal plate and the insulating base between which the electronic element is mounted. A flexible substrate having a wiring conductor connected to the metal plate, wherein the metal plate has a hole penetrating in the thickness direction, and the hole of the metal plate is an upper surface from a lower surface side of the metal plate. The side is big .

  According to another aspect of the present invention, an electronic device includes an electronic element mounting package having the above-described configuration, and an electronic element mounted on the electronic element mounting package and electrically connected to the wiring conductor. It is characterized by that.

An electronic device mounting package according to one aspect of the present invention is sandwiched between a metal plate as a base, an insulating base having an insulator, and the metal plate and the insulating base, and is electrically connected to the electronic device to be mounted. The metal plate has a hole penetrating in the thickness direction, and the hole of the metal plate is larger on the upper surface side than the lower surface side of the metal plate. It is possible to efficiently dissipate the heat generated when the electronic element is operated to the outside through the base metal plate, and to reduce the thermal stress due to the difference in thermal expansion between the metal plate and the flexible substrate. It becomes possible to relax by the holes, it is possible to suppress the warpage of the package due to thermal stress, and the electronic element can be operated stably.

  According to another aspect of the present invention, the electronic device includes the electronic device mounting package having the above-described configuration, whereby the electronic device can operate stably.

(A) is a longitudinal cross-sectional view which shows the electronic device in embodiment of this invention, (b) is a bottom view of (a). It is a principal part expanded vertical sectional view in the other example of the electronic device in embodiment of this invention. (A) And (b) is a bottom view which shows the other example of an electronic device. It is a longitudinal cross-sectional view which shows the electronic device in a comparative example. It is a graph which shows the simulation result of the electronic device which has the hole penetrated in the metal plate shown in Drawing 1, and the wiring board of a comparative example.

  Exemplary embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, an electronic device 1 according to an embodiment of the present invention includes an electronic element mounting package and an electronic element 8 mounted on the electronic element mounting package. For example, the electronic device 1 is connected to a printed circuit board constituting an electronic module using a bonding material.

  The electronic element mounting package includes a metal plate 5 serving as a base, an insulating base 2, and a flexible substrate 3.

  The insulating base 2 is composed of a plurality of insulating layers (also referred to as insulators) 2a to 2c stacked on each other. The insulating layers 2a to 2c are made of, for example, a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, a silicon nitride sintered body, a mullite sintered body, or a glass ceramic, Alternatively, it is made of an organic insulating material such as an organic resin material such as polyimide, epoxy resin, fluororesin, polynorbornene or benzocyclobutene, or a composite insulating material in which a ceramic material powder is dispersed in an organic resin material. . The insulating base 2 is formed by a substrate forming means such as a ceramic green sheet lamination method or an additive method.

If the insulating substrate 2 is made of, for example, an aluminum oxide sintered body, first, an appropriate organic binder and solvent are added to and mixed with the raw material powder such as aluminum oxide, silicon oxide, calcium oxide or magnesium oxide, and the slurry is mixed. The ceramic green sheet used as the insulating layers 2a-2c is obtained by making this into a sheet form by a sheet forming method such as a doctor blade method. This ceramic green sheet is cut into an appropriate size, and laminated to prepare a laminated body. The laminated body is fired at a temperature of about 1,600 ° C. in a reducing atmosphere to thereby form a plurality of insulating layers 2a to 2c. The insulating base 2 laminated with is manufactured.

The insulating base 2 is provided with a wiring conductor. As the wiring, for example, a connection electrode that is electrically connected to the electronic element is provided on the upper surface of the insulating substrate 2, and a terminal electrode that is connected to the wiring conductor 4 of the flexible substrate 3 is provided on the lower surface of the insulating substrate 2. Inside the insulating base 2, an internal wiring including a through conductor is provided for electrically connecting the connection electrode and the terminal electrode. If the insulating base 2 is made of, for example, a ceramic material, the wiring is made of, for example, tungsten (W), molybdenum (Mo), molybdenum-manganese (Mo-Mn), copper (Cu), silver (Ag), or silver- A metal material such as palladium (Ag—Pd) can be used. In the step of manufacturing the insulating base 2 described above, tungsten (W), molybdenum (Mo), molybdenum-manganese (Mo-Mn), copper (Cu), silver (Ag), silver-palladium (Ag-Pd), or the like. A conductive paste obtained by adding and mixing an appropriate organic binder and solvent to the powder is preliminarily printed and applied in a predetermined pattern on a ceramic green sheet to be an insulating substrate 2 by a screen printing method. By baking at the same time as the sheet, the insulating base 2 is deposited on a predetermined position. When the wiring is a through conductor, it is formed by forming a through hole in the green sheet by punching by a die or punching or laser processing, and filling this through hole with a conductor paste for wiring by a printing method Is done.

  If the insulating substrate 2 is made of, for example, an epoxy resin, first, a substrate made of glass epoxy resin obtained by impregnating a glass fiber woven cloth with the epoxy resin is used as the lowermost insulating layer 2c, and a liquid is formed on the upper surface thereof. The insulating layer 2b is formed by applying a thermosetting or photosensitive epoxy resin precursor by spin coating or curtain coating, and curing it by heating or irradiating light such as ultraviolet rays. . Furthermore, a plurality of insulating layers 2a to 2c are formed by repeatedly forming an insulating layer on this according to the required number of layers.

  If the insulating substrate 2 is made of an organic resin material, the wiring adopts the insulating layer formed as described above and the copper layer using a thin film forming technique such as an electroless plating method or an evaporation method, and a photolithography technique. It is produced by. For example, an insulating layer having a through hole is formed using a photosensitive resin, a mask having a predetermined pattern shape is formed on the insulating layer, and the inside of the through hole and the surface of the insulating layer are formed by a sputtering method, a vacuum evaporation method, or a plating method. A metal thin film having a predetermined shape may be formed on the substrate. Alternatively, after forming a metal thin film on the entire upper surface of the insulating layer without forming a mask, a mask having a predetermined shape may be formed and unnecessary portions may be removed by etching. Or you may form a wiring conductor and an electrode by processing the metal foil which consists of copper, for example in a predetermined shape, and transcribe | transferring on an insulating layer.

  In the example shown in FIG. 1, the electronic element 8 and the electrode 7 formed on the flexible substrate 3 are connected via a wiring including a through conductor formed on the insulating base 2. The electrode 7 is connected to the wiring conductor 4 through the through conductor of the flexible substrate 3. Note that a frame-shaped insulating substrate 2 may be used, and the electronic element 8 may be mounted on the flexible substrate 3 exposed in the frame of the insulating substrate 2.

  The flexible substrate 3 is sandwiched between the metal plate 5 and the insulating base 2 and has a wiring conductor 4 that is electrically connected to the mounted electronic element 8. Specifically, for example, an insulating layer, a wiring conductor 4, an adhesive layer (not shown) inside the flexible substrate 3, and a cover layer are included. If the insulating layer is made of, for example, a polyimide layer, a copper foil is pressure-bonded on the upper and lower sides of the insulating layer to be a film-like base via an adhesive layer, and then a wiring conductor 4 is formed by etching treatment. The flexible substrate 3 can be formed by laminating a cover layer thereon.

The wiring conductor 4 forms a transmission line with a signal wiring conductor and a ground wiring conductor, and the wiring width and thickness of the signal wiring conductor or between the signal wiring conductor and the ground wiring conductor. The characteristic impedance can be set to an arbitrary value (generally, 50Ω for single wiring and 100Ω for differential wiring) by setting the distance or the thickness of the insulating layer or cover layer . It is possible to realize the electronic apparatus 1 with improved signal transmission characteristics by means of the signal transmission path in which the characteristic impedance is matched. The transmission line may be a structure suitable for transmitting a high-frequency signal, and may be, for example, a microstrip line, a strip line, a coplanar line, or a differential line structure including two parallel line conductors.

  The wiring conductor 4 and the electrode 7 formed on the flexible substrate 3 are, for example, copper (Cu), silver (Ag), nickel (Ni), chromium (Cr), titanium (Ti), gold (Au), niobium (Nb Or a thin film made of a metal material such as an alloy thereof.

In FIG. 1, a metal plate 5 is provided on the lower surface of the flexible substrate 3, and a hole 6 that penetrates in the thickness direction is formed in the metal plate 5, that is, a hole 6 through which the metal plate 5 penetrates in the thickness direction. It has become. Thus, by providing the metal plate 5 on the lower surface of the flexible substrate 3, heat generated when the mounted electronic element 8 operates can be efficiently dissipated to the outside through the metal plate 5. Is possible. Further, a metal plate 5 is provided on the lower surface of the flexible substrate 3, and the metal plate 5 has a hole 6 that penetrates in the thickness direction, so that heat due to a difference in thermal expansion between the metal plate 5 and the flexible substrate 3 can be obtained. The stress can be relaxed by the holes 6, and the warpage of the package due to the thermal stress can be suppressed. Therefore, the electronic element can be stably operated.

  Moreover, it is preferable that the hole 6 of the metal plate 5 is provided at a position overlapping the wiring conductor 4 in a plan view. In the flexible substrate 3, the characteristic impedance of the wiring conductor 4 may be different between a portion sandwiched between the metal plate 5 and the insulating base 2 and a portion not sandwiched between the metal plate 5 and the insulating base 2. Specifically, in the portion sandwiched between the metal plate 5 and the insulating base 2, the metal plate 5 as a conductor is close to the wiring conductor 4 of the flexible substrate 3, so that the impedance is lowered. Since the metal plate 5 has the hole 6 penetrating in the thickness direction at a position overlapping the wiring conductor 4, the impedance of the portion overlapping the hole 6 in the wiring conductor 4 can be made higher than the impedance of the portion not overlapping. Therefore, since the characteristic impedance of the wiring conductor 4 of the flexible substrate 3 in the portion sandwiched between the metal plate 5 and the insulating substrate 2 can be increased, the characteristic impedance of the portion sandwiched between the metal plate 5 and the insulating substrate 2 can be increased. Can be brought close to the impedance of the portion not sandwiched between the metal plate 4 and the insulating substrate. As a result, stable operation can be ensured even when high-speed signals are transmitted.

  The size of the hole 6 penetrating in the thickness direction is such that the length in the width direction of the wiring conductor 4 is at least three times the wiring width of the wiring conductor 4, and the length in the length direction of the wiring conductor 4 is set to the flexible substrate 3. Is made smaller than 1/16 of the wavelength of the transmitted signal, the characteristic impedance of the wiring conductor 4 can be increased, and the transmitted signal can be prevented from leaking from the hole 6 penetrating in the thickness direction.

  As shown in FIG. 2, the hole 6 penetrating in the thickness direction of the metal plate 5 is preferably larger on the upper surface side than the lower surface side of the metal plate 5. When the upper surface side is larger than the lower surface side of the metal plate 5, heat from the electronic element 8 can be transmitted to the lower surface direction of the metal plate 5 while diffusing in the plane direction, and it can be more efficiently dissipated to the outside. ,preferable.

  Further, as shown in FIG. 2, when the hole 6 of the metal plate 5 is gradually increased from the upper surface to the lower surface, the distance between the metal plate 5 and the wiring conductor 4 is temporarily increased. Thus, the change in the characteristic impedance is moderate, and the occurrence of reflection noise due to the abrupt change in the characteristic impedance can be suppressed. The upper surface side of the hole 6 penetrating in the thickness direction is at least larger than the thickness of the metal plate 5 than the lower surface side, that is, the angle between the lower surface of the metal plate 5 and the inner surface of the hole 6 is 45 degrees or less. Thus, an increase in reflection noise due to a sudden change in the characteristic impedance of the wiring conductor 4 can be suppressed.

Here, a specific example of the structure shown in FIG. 2 will be described. The relative permittivity of the insulating base 2 is 10.0, the wiring width of the wiring conductor 4 is 50 μm, and the maximum signal transmitted through the wiring conductor 4 is maximum. When the frequency is 5 GHz, the size of the hole 6 penetrating in the thickness direction is 150 μm or more which is three times the wiring width of the wiring conductor 4 and about 1.2 mm or less which is 1/16 of the signal wavelength. That's fine.

Further, as shown in FIG. 3A, when the hole 6 of the metal plate 5 is provided only at a position overlapping the wiring conductor 4 in a plan view, the characteristic impedance of the wiring conductor 4 can be increased. It is possible to keep the mechanical strength of the metal plate 5 moderately, which is preferable. Note that the hole 6 of the metal plate 5 is good because the center of the hole 6 overlaps the center of the wiring conductor 4 in the width direction when seen in a plan view, so that the bias of the characteristic impedance with respect to the wiring conductor 4 can be eliminated. Can transmit a simple signal.

  Further, as shown in FIG. 3B, when the arrangement of the wiring conductor 4 is biased in the region where the metal plate 5 and the flexible substrate 3 overlap, the hole 6 is also formed at a position where the wiring conductor 4 does not overlap. It is preferable to provide the holes 6 so that the arrangement of the holes 6 is not biased, because the distribution of thermal stress does not occur and the warpage of the package can be suppressed. For example, in the example of FIG. 3, the wiring conductor 4 exists only on the right side of the center line c of the metal plate 5, but the hole 6 is also provided on the left side of the center line c. At this time, the holes 6 are arranged so as to be symmetric with respect to the center line c. The holes 6 are also arranged symmetrically in the vertical direction, and the holes 6 are arranged without any bias.

  Hereinafter, the electronic device 1 shown in FIG. 2 (electronic element mounting package having a hole 6 penetrating the metal plate 5) and the electronic device 41 of a comparative example (electronic element mounting package not having the hole 6 in the metal plate 45) ) And the transmission result simulation result will be described with reference to FIG.

FIG. 5 is a graph showing the reflection characteristics of the electronic device mounting package, in which the horizontal axis indicates the frequency and the vertical axis indicates the reflection amount S11 in decibels. In FIG. 5, the solid line indicates the characteristic in the case of the electronic device 1 of the present embodiment, and the broken line indicates the characteristic in the case of the electronic device 41 of the comparative example.

  In the simulation model of the electronic device mounting package of the present embodiment, the insulating substrate 2 has a dielectric constant of 10.0, a size of 10 mm square, a thickness of 250 μm, and a flexible substrate 3 having a thickness of 107.5 μm (the wiring layer is 18 μm, insulating layer 25 μm, adhesive layer 52 μm, cover layer 12.5 μm), wiring width of wiring conductor 4 is 40 μm, wiring thickness is 18 μm, and distance between wirings is 40 μm. The size is 10 mm square, the thickness is 50 μm, and the through holes 6 are 400 μm square in size and are formed so as to overlap the wiring conductor 4 at an 800 μm pitch. In this case, the characteristic impedance of the wiring conductor 4 is 81.4Ω, which is the average of the characteristic impedance of the portion where there is no hole 6 penetrating the metal plate 5 and the characteristic impedance of the portion of the hole 6 penetrating the metal plate 5. The characteristic impedance of the wiring conductor 4 of the flexible substrate 3 in a portion not sandwiched between the bases 2 is closer to 84.6Ω.

  On the other hand, the electronic element mounting package of the comparative example is the same as that shown in FIG. 4 except that the size of the insulating base 42 is 10 mm square and there is no through hole 6. . In this case, the characteristic impedance of the wiring conductor 44 is 80.0Ω.

As shown in FIG. 5, the electronic device 41 of the comparative example has a reflection characteristic up to 5 GHz.
The maximum reflection amount is -13.1 dB at 4.2 GHz, whereas the maximum reflection amount is -14.4 dB at 4.1 GHz in the wiring board of the present embodiment. ing.

  Therefore, in the electronic device mounting package shown in FIG. 2, the characteristic impedance of the wiring conductor 4 of the flexible substrate 3 in the portion sandwiched between the metal plate 5 and the insulating base 2 is effectively increased, and the metal Since the impedance can be matched with the characteristic impedance of the wiring conductor 4 of the flexible substrate 3 in the portion not sandwiched between the plate 5 and the insulating base 2, the reflection characteristic can be improved.

According to the electronic element mounting package of the present embodiment, the metal plate 5 as a base, the insulating base 2 made of an insulator, and the metal plate 5 and the insulating base 2 are sandwiched between the electronic element 8 to be mounted. And the flexible substrate 3 having the wiring conductor 4 to be electrically connected, and the metal plate 5 has the hole 6 penetrating in the thickness direction, so that the mounted electronic element is operated. It is possible to efficiently dissipate the heat generated at the time to the outside through the base metal plate, and to relieve the stress due to the difference in thermal expansion between the metal plate 5 and the flexible substrate 3 through the holes 6. It is possible to suppress warping due to stress due to the difference in thermal expansion between the metal plate 5 and the flexible substrate 3, to suppress disconnection in the electronic device, and to allow the electronic element to operate stably. Can do.

  According to the electronic device of the present embodiment, the electronic element can be stably operated by having the electronic element mounting package having the above-described configuration.

1: Electronic device 2: Insulating substrate 3: Flexible substrate 4: Wiring conductor 5: Metal plate 6: Hole 7: Electrode 8: Electronic element

Claims (3)

A metal plate,
An insulating substrate;
A flexible substrate having a wiring conductor sandwiched between the metal plate and the insulating base and electrically connected to the mounted electronic element;
The metal plate has a hole penetrating in the thickness direction ,
The package for mounting an electronic device , wherein the hole of the metal plate has a larger upper surface side than a lower surface side of the metal plate .   2. The electronic element mounting package according to claim 1, wherein the hole of the metal plate is provided at a position overlapping the wiring conductor in a plan view. The electronic device mounting package according to claim 1 or 2 ,
An electronic device comprising: an electronic device mounted on the electronic device mounting package and electrically connected to the wiring conductor.