JP5740458B2 - Optical semiconductor package - Google Patents

Description

  The present invention relates to an optical semiconductor package, and more particularly to an optical semiconductor package structure that realizes a low thermal resistance.

  A conventional optical semiconductor package will be described with reference to the drawings.

  FIG. 3A is a front view showing an example of a conventional optical semiconductor package, and FIG. 3B is an enlarged view of a region within a broken line in FIG.

  The optical semiconductor package 50 shown in the figure includes a lead frame 53 made up of two metal pieces 51 and 52, an optical semiconductor element 22 fixed on the lead frame 53 via a conductive adhesive 54, and a resin sealing body. 56.

  As shown in FIG. 3B, the optical semiconductor element 22 has a cathode electrically connected to the metal piece 51 of the lead frame by a conductive adhesive 54, and an anode connected to the lead frame 53 via the metal wire 26. The metal piece 52 is electrically connected.

  In the conventional optical semiconductor package as shown in FIG. 3, the optical semiconductor element 22 generates heat in proportion to the input current when energized. The generated heat is conducted to the conductive adhesive 54, then to the lead frame 53, and then released to the outside air. A part of the heat is released to the outside air via the sealing resin 56. However, since the lead frame 53 is generally formed of a metal having a very good thermal conductivity, most of the heat is generated in the lead frame. 53 is released.

  The characteristics of the optical semiconductor element are deteriorated by a temperature rise due to heat, and as a result, the light extraction efficiency is lowered. Conventionally, in order to cope with such problems by improving heat dissipation and reducing the thermal resistance of the package, the following methods have been adopted for lead frame type packages.

  That is, the first method is to increase the lead frame width, the second method is to select a conductive adhesive with good thermal conductivity, and the third method is to increase the capacity of the entire package. And so on.

  In some cases, a stem type having a low thermal resistance of the package is used instead of the lead frame type.

  However, semiconductor devices are generally required to be lighter and thinner. On the other hand, according to the first and third methods described above, the volume of the package is increased. According to the second method, the volume of the package is not affected, but a significant effect cannot be expected. In addition, the stem type package is not suitable for mass production because the unit cost is high and a large number of parts must be assembled.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a lead frame type optical semiconductor package that realizes a low thermal resistance.

According to the present invention,
An optical semiconductor element;
A lead frame for mounting the optical semiconductor element on a main surface;
A resin molding disposed so as to cover the optical semiconductor element;
With
The lead frame has a first region located on the opposite side of the back surface opposite to the main surface on which the optical semiconductor element is mounted, and is exposed to the outside through the bottom of the resin molded body. Formed to form a first heat dissipation area, the outer lead portion has a shape protruding outward from the resin molded body, and the outer area from the resin molded body forms a second heat dissipation area,
The first region of the lead frame and the back surface of the outer end portion of the lead frame are located on substantially the same plane,
An optical semiconductor package is provided.

According to the present invention,
An optical semiconductor element;
A translucent resin molding disposed so as to cover the optical semiconductor element;
A lead frame for mounting the optical semiconductor element;
A light-shielding resin molding that supports the lead frame and the translucent resin molding;
With
The lead frame is separate from the first part for mounting the optical semiconductor element on the main surface and the first part, and from the inside of the light shielding resin molded body to the outside of the light shielding resin molded body. A plurality of second portions formed to extend, and
The first portion of the lead frame is formed so that the back surface thereof penetrates the bottom of the light-shielding resin molded body and protrudes downward to form a first heat dissipation region, and the first portion of the second portion The outer region from the light-shielding resin molded body forms a second heat dissipation region, and the back surface of the first portion and the back surface of the outer end portion of the second portion are located on substantially the same surface.
An optical semiconductor package is provided.

  According to the present invention, the lead frame is held by the light-shielding resin molded body, and the region corresponding to the optical semiconductor element mounting region of the back surface facing the main surface is exposed from the bottom of the light-shielding resin molded body. Since one heat dissipation region is formed, heat generated in the optical semiconductor element is released to the outside with high efficiency. As a result, an optical semiconductor package with significantly reduced thermal resistance is provided.

  Hereinafter, some embodiments of the present invention will be described with reference to the drawings.

  In the following drawings, the same parts as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

(1) First Embodiment First, a first embodiment of an optical semiconductor package according to the present invention will be described with reference to FIG. As shown in the figure, the feature of the present embodiment is that a lead frame 13 that releases heat generated by the optical semiconductor element in the horizontal direction and the bottom surface direction, and holds the lead frame 13 and supports the translucent member 16. The light-shielding resin molding 14 is provided.

  1A and 1B are explanatory views showing an optical semiconductor package 1 of the present embodiment, where FIG. 1A is a plan view, FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A, and FIG. Sectional drawing in the BB cut surface of is shown.

  The optical semiconductor package 1 shown in FIG. 1 includes a lead frame 13, an optical semiconductor element 22, a light-shielding resin molded body 14, and a translucent resin molded body 16.

  As shown in FIG. 1A, the lead frame 13 includes a metal piece 12 that is a first metal part and a metal piece 11 that is a second metal part. The metal piece 12 is formed in a substantially T-shape having an inner lead portion and an outer lead portion extending from the inner lead portion in the vertical direction and the left direction in the drawing. An anchor hole 18 is provided in the boundary region between the inner lead portion and the outer lead portion of the metal piece 12 to enhance the adhesion between a light-shielding resin molded body and a translucent resin molded body, which will be described later. Further, the metal piece 11 is formed in a substantially striped shape so that the tip of the inner lead portion is separated from the metal piece 12 by a predetermined distance and extends in the right direction on the paper surface.

  Both of these metal pieces 11 and 12 can be formed by press working or casting, and the outer lead portion of each metal piece 11 and 12 forms a second heat dissipation region.

  Further, as shown in FIGS. 4A and 4B, the metal piece 12 is formed so that the region excluding the element mounting region at the center of the inner lead portion and each end portion of the outer lead portion is higher than the bottom surface of the package. , Bent in the vertical direction. With such a shape, the element mounting region of the metal piece 12 and each end portion of the outer lead portion are in contact with the main surface of the substrate (not shown) on which the optical semiconductor package 1 is mounted on the bottom surface, and other regions. Is insulated from the wiring on the substrate.

  The optical semiconductor element 22 is placed on the mounting area of the metal piece 12 and is fixed to the main surface of the metal piece 12 by the conductive adhesive 24. As a material of the conductive adhesive 24, Ag (silver) paste is preferable in consideration of heat resistance of the light-shielding resin molding 14 described later. In this embodiment, the optical semiconductor element 22 is an LED (Light Emitting Diode), and one of the terminals, for example, the cathode, is electrically connected to the metal piece 12.

  Further, in the optical semiconductor element 22, another terminal, for example, an anode is electrically connected to the metal piece 11 through the metal wire 26.

  The light-shielding resin molded body 14 constitutes a second resin molded body in this embodiment, and the bottom portion and the cylindrical side portion are integrally formed of the light-shielding resin. As a result, the metal pieces 11 and 12 forming the lead frame 13 are held by the side portions of the light-shielding resin molded body 14 in the boundary region between the outer lead portion and the inner lead portion. It is supported by the bottom principal surface of the light-shielding resin molding 14 except for the element mounting region. Moreover, the side part upper surface of the light-shielding resin molding 14 is formed so as to have a shape that forms a plurality of steps whose height gradually decreases as it approaches the center point.

  The above-described shape of the light-shielding resin molding 14 can be easily formed by setting the lead frame 13 in a predetermined mold so that the main surface is the lower surface and pouring the light-shielding resin into the mold.

  The translucent resin molded body 16 constitutes the first resin molded body in the present embodiment, and is molded so as to have a lens shape capable of obtaining optical directivity on the optical axis of the LED.

  In this embodiment, the translucent resin molded body 16 is a translucent resin in which a mold molded according to a desired lens shape is placed on a predetermined step on the upper surface of the side portion of the light-shielding resin molded body 14. It is molded by pouring. As described above, since the anchor hole 18 is provided in the metal piece 11, the translucent resin 16 is bonded to the light-shielding resin molded body 14 through the anchor hole 18, thereby the translucent resin molded body. 16 firmly adheres to the light-shielding resin molding 14. As the material of the light-shielding resin, a resin having a refractive index close to that of the lens itself, for example, a gel-like silicon transparent resin is used.

The molding of the translucent resin molded body 16 is not limited to the above method. For example, a hemisphere whose optical characteristics are adjusted with the LED is formed in advance using a translucent resin. The same translucent resin as that of the material may be poured to a height corresponding to the bottom surface of the hemisphere so as to cover the LED, and a pre-formed hemisphere may be placed and fixed thereon. Further, instead of being integrally fixed with the light-transmitting resin, for example, dry nitrogen (N ₂ ) may be filled and only the hemisphere may be fixed to the corresponding step on the side surface of the light-shielding resin molded body 14. good.

  According to the optical semiconductor package 1 of the present embodiment, the back surface side of the element formation region in the inner lead portion of the lead frame 13 is exposed to the outside of the package to form the first heat dissipation region, and further in the outer lead portion of the lead frame 13 Since the four second heat radiation areas extending to the outside of the package are provided, the thermal resistance can be greatly reduced as compared with the conventional package. Further, the light-shielding resin molded body 14 serves as a base to hold the lead frame 13, and the light-shielding resin molded body 14 is fixed to and supports the light-transmitting resin molded body 16, so that it has excellent adhesiveness. It is possible to reliably prevent moisture and contaminants from entering from the outside. In addition, since a plurality of step portions are provided on the upper surface of the side part of the light-shielding resin molded body 14, the distance between the light-transmitting resin molded body 16 and the LEDs 22 can be easily adjusted. Further, the area of the back surface of the lead frame 13 that does not directly contribute to heat dissipation is formed so as to be separated from the bottom surface of the translucent resin molded body 16 by a predetermined distance. It does not interfere with the degree of freedom.

(2) Second Embodiment Next, a second embodiment of the optical semiconductor package according to the present invention will be described with reference to FIG.

  2A and 2B are explanatory views of the optical semiconductor package 2 of the present embodiment, in which FIG. 2A is a plan view thereof, and FIG. 2B is a cross-sectional view taken along the line CC in FIG.

  In contrast to the optical semiconductor package 1 shown in FIG. 1, the optical semiconductor package 2 shown in FIG. 2 is characterized by the structure of the lead frame 34.

  That is, the optical semiconductor package 2 of this embodiment includes a metal block 33 and a metal piece 32 instead of the metal piece 12 shown in FIG. The metal block 33 is integrally formed in a shape in which two concentric discs having different radii are stacked, and a notch is formed in the top disc portion so as to form an inclined surface S1 whose side surface is lowered toward the center. LED22 is mounted in the bottom face. The LED 22 is fixed to the bottom surface of the notch by the conductive adhesive 24 and is electrically connected to the metal block 33. Moreover, the bottom part of the metal block 33 has a disk shape with a larger radius than the top part, and the radius is substantially the same as the translucent resin molded body 16 in this embodiment. Further, the light-shielding resin molding 36 is formed so that the bottom of the metal block 33 protrudes from the bottom surface. With such a shape, the metal block 33 is connected to the wiring on the substrate (not shown) on the bottom surface, and the bottom surface except the large bottom area of the metal block 33 and the region corresponding to the mounting region of the light-shielding resin molded body 36 Heat generated by the LED 22 is efficiently released by the gap between the substrate and the substrate.

  Further, the inclined surface S1 formed in the top notch of the metal block 33 reflects the light deviating from the optical axis of the LED 22 and enters the translucent resin molded body 16, and has a trajectory substantially parallel to the optical axis. Radiated to the outside.

  Further, as shown in FIG. 2B, the side portion of the light-shielding resin molded body 36 has an inclined shape whose inner side is lowered toward the center, and the surface S2 is coated with a reflective material and is white. It has a glossy surface. Therefore, the light that deviates from the optical axis is also reflected by the inclined surface S2, and is emitted in a trajectory parallel to the optical axis through the translucent resin molded body 16.

  In the present embodiment, the cathode of the LED 22 is configured to be connected to the wiring on the substrate via the metal block 33. However, the present invention is not limited to this, for example, according to the design of the substrate to be mounted. Of course, the top peripheral region of the metal block 33 and the tip of the metal piece 32 may be connected by a metal wire 27 and connected to the wiring on the substrate by the end of the metal piece 32 outside the package, as shown by the broken line. .

It is explanatory drawing of 1st Embodiment of the optical semiconductor package concerning this invention. It is explanatory drawing of 2nd Embodiment of the optical semiconductor package concerning this invention. It is the front view and enlarged view which show an example of the optical semiconductor package by a prior art.

1, 2 Optical semiconductor package 11, 12, 31, 32 Metal piece 13, 34 Lead frame 14, 36 Light-shielding resin molding (first resin molding)
16 Translucent resin molding (second resin molding)
22 Optical semiconductor device (LED)
24 conductive adhesive 26, 27 metal wire S1, S2 inclined surface

Claims (4)

An optical semiconductor element;
A first resin molding in contact with the optical semiconductor element;
A first of the first lead frame electrode and Ru is connected in the optical semiconductor device in a first plane,
A plurality of parts arranged so as to be separated from the first lead frame and extend to the outside of the first resin molded body, and one of which is connected to the second electrode of the optical semiconductor element via a conductor. A second lead frame of
And the second resin molded body you supporting said first and second lead frame and the first resin molded body,
With
The second surface opposite to the first surface is exposed to the outside of the second resin molding ,
One end of the second lead frame is in contact with the first and second resin moldings, and the other end is exposed to the outside of the second resin molding,
The second surface and the other end are located on substantially the same surface,
In the second lead frame, the one end and the other end are shifted in a direction perpendicular to the extending direction in a plan view parallel to the first surface.
Optical semiconductor device . The optical semiconductor device according to claim 1, wherein a size of the second surface is larger than a size of the first surface . The first lead frame has a recess formed in a mounting region of the optical semiconductor element,
The optical semiconductor device according to claim 1, wherein a side surface of the concave portion forms an inclined surface that reflects light. 4. The surface of the second resin molded body opposite to the first resin molded body side is located on the first resin molded body side with respect to the substantially same surface. 5. An optical semiconductor device according to any one of the above.

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