JP2006261242A - Lead frame and optical semiconductor device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead frame ensuring sufficient close contact with a resin of package, and also to provide an optical semiconductor device using the same. <P>SOLUTION: The lead frame comprises a mount head 12 including a reflecting plate 11, a first lead terminal 13 extended from the mount head 12 in a first direction, a second lead terminal 14 provided separately from the mount head 12 and extended in the second direction opposing to the first direction from the mount head 12, and a third lead terminal 16 provided separately from the mount head 12 having a projected region 15 in the first or second direction and in the direction where the mount head 12. For the integral molding of the lead frame 10 with resin, close contact between the lead frame 10 and resin is maintained with the resin supplied and solidified in a gap between the side 12a of the mount head 12 and the side 15a of the projected region 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead frame and an optical semiconductor device using the lead frame, and more particularly to a lead frame having a structure suitable for obtaining sufficient adhesion with a resin of a package and an optical semiconductor device using the lead frame.

  Light emitting diodes (LEDs) are widely used as light sources for AF (Auto Focus) such as DSC (Digital Still Camera) in addition to full-color displays, traffic / signal devices, and in-vehicle applications.

  2. Description of the Related Art Conventionally, in an optical semiconductor device having a surface mount type package capable of reducing the mounting height, an optical semiconductor element is mounted on a concave reflecting plate portion of a substantially flat lead frame, and the optical semiconductor element is mounted on the lead frame. After wire bonding to the lead terminal, the lead frame and the optical semiconductor element were integrally molded with resin so as to extend the lead terminal to the outside (see, for example, Patent Document 1).

  An optical semiconductor device disclosed in Patent Document 1 includes a lead frame in which a concave reflector and an anode terminal, first, second, and third cathode terminals are formed, and an inner bottom portion of the concave reflector. A package formed of a light-reflective synthetic resin integrally with the lead frame so as to extend each terminal to the outside, and an optical semiconductor element fixed to the inner bottom of the reflector, A light emitting portion is provided in which the light transmitting material is provided in a predetermined shape, for example, a condensing lens shape, in the reflecting portion and the reflecting plate portion.

  However, the optical semiconductor device disclosed in Patent Document 1 uses a lead frame having a large mount head area for mounting an optical semiconductor element in which three cathode terminals are connected to a reflector plate and connected in common. When the lead frame is molded with resin, the contact area between the lead frame and the package resin increases.

Since the adhesion between the lead frame and the resin is weak, there is a problem that the larger the contact area, the more easily the resin is peeled from the lead frame due to the difference in thermal expansion between the lead frame and the resin of the package in the surface mounting reflow process.
Japanese Patent Laying-Open No. 2004-95576 (page 3-4, FIG. 6)

  The present invention provides a lead frame having sufficient adhesion to a package resin and an optical semiconductor device using the lead frame.

  A lead frame according to an aspect of the present invention is provided with a mount head having a reflecting plate portion, a first lead terminal extending from the mount head in a first direction, and spaced from the mount head. A second lead terminal extending in a second direction opposite to the first direction, and spaced apart from the mount head, the first direction or the second direction, wherein the mount head is And a third lead terminal having a convex portion in the provided direction.

  An optical semiconductor device according to an aspect of the present invention is provided with a mount head having a reflecting plate portion, a first lead terminal extending from the mount head in a first direction, and spaced from the mount head, A second lead terminal extending from the mount head in a second direction opposite to the first direction, and provided spaced apart from the mount head, the first direction or the second direction, A lead frame including a third lead terminal having a convex portion in a direction in which the mount head is provided, an optical semiconductor element mounted on an inner bottom portion of a reflector, and the optical semiconductor element as the second lead terminal A connection conductor that is electrically connected to the lead frame; and a package in which the lead frame and the optical semiconductor element are molded.

  According to the present invention, a lead frame having sufficient adhesion to a package resin and an optical semiconductor device using the lead frame can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  A lead frame according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a view showing a lead frame, FIG. 1 (a) is a plan view thereof, FIG. 1 (b) is a sectional view taken along the line AA of FIG. 2 is a perspective view showing a state in which the lead frame is used.

  As shown in FIG. 1, the lead frame 10 of the present embodiment extends in the first direction (downward in the figure) from the mount head 12 having a concave reflector 11 at the center and the mount head 12. A first lead terminal 13 and a second lead terminal 14 provided apart from the mount head 12 and extending in a second direction opposite the first direction from the mount head 12 and provided away from the mount head 12. And a third lead terminal 16 having a convex portion 15 in the first direction or the second direction and in the direction in which the mount head 12 is provided.

  The lead frame 10 is, for example, a copper plate plated with nickel and silver having a thickness of about 0.15 mm, and the mount head 12 and the first to third lead terminals 13, 14, and 16 are formed by pressing.

  The mount head 12 has a substantially octagonal shape, and an optical semiconductor element (not shown) is mounted on the inner bottom portion 17 of the reflection plate portion 11 at the center thereof. The inner bottom portion 17 is formed at a height substantially equal to that of the first to third lead terminals 13, 14, 16.

  The first lead terminal 13 extending from the mount head 12 becomes a cathode terminal of the optical semiconductor element, and the second lead terminal 14 is wire-bonded to the optical semiconductor element and becomes an anode terminal of the optical semiconductor element.

The third lead terminal 16 is provided on both sides of the first lead terminal 13 and both sides of the second lead terminal 14.
The convex portion 15 of the third lead terminal 16 has a side 15 a that is spaced apart and opposed along a part of the side 12 a on the outer periphery of the mount head 12.

The distance L1 between the side 12a of the mount head 12 and the side 15a of the convex portion 15 is set to, for example, about three times the thickness of the lead frame 10 and about 0.4 to 0.5 mm.
The length L2 of the side 15a of the convex portion 15 that faces the side 12a of the mount head 12 is set shorter than the length of the side 12a of the mount head 12, for example.

  A broken line 18 shows a package in which the lead frame 10 is molded with resin, and the inside of the broken line 18 is a portion molded with resin.

Further, the first lead terminal 13 and the third lead frame 16 provided on both sides of the first lead terminal 13 are connected by the connecting bar 20, and the lead terminals 21 and 22 extend in one direction from both ends of the connecting bar 20. Yes.
Similarly, the second lead terminal 14 and the third lead frame 16 provided on both sides of the second lead terminal 14 are connected by the connecting bar 23, and the lead terminals 24 and 25 extend in one direction from both ends of the connecting bar 23. ing.

  As shown in FIG. 2, in the lead frame 10, the optical semiconductor 27 is mounted on the reflecting plate portion 11 of the mount head 12, and the upper electrode of the optical semiconductor 27 is connected to the bonding portion 29 of the second lead terminal 14 by the wire 28. Has been.

  Each lead terminal is used by being bent in a U shape so as to enclose the package 18 as a whole.

That is, the first lead terminal 13 and the third lead terminal 16 provided on both sides of the first lead terminal 13 are bent downward at the portions extending from the package 18, and the leading ends of the lead terminals 21 and 22 are further package 18. It is bent to the lower side.
Similarly, the second lead terminal 14 and the third lead terminal 16 on both sides of the second lead terminal 14 are bent downward at the portions extending from the package 18, and the leading ends of the lead terminals 24 and 25 are below the package 18. It is bent to the side.

Next, an optical semiconductor device using the lead frame 10 will be described with reference to FIGS.
The optical semiconductor device of this embodiment is an example when used as an AF light source of a DSC. FIG. 3 is a perspective view in which the inside of the optical semiconductor element is seen through, and FIG. 4 is cut along the line BB in FIG. It is sectional drawing seen in the arrow direction.

  As shown in FIG. 3, the optical semiconductor device 30 includes a lead frame 10, an optical semiconductor element 27 mounted on the inner bottom portion 17 of the reflector 11 of the mount head 12, an upper surface electrode of the optical semiconductor element 27, and a second lead. The wire 28 that electrically connects the bonding portion 29 of the terminal 14 and one side of the first to third lead terminals 13, 14, 16 extend to the outside, and the lead frame 10 and the optical semiconductor element 27 are made of a translucent resin. A package 31 is integrally molded.

The package 31 includes a base portion 32 that molds the lead frame 10 and the optical semiconductor element 27, and a lens portion 33 that condenses light emitted from the optical semiconductor 27.
The light from the optical semiconductor element 27 collected by the lens unit 33 is applied to a DSC subject (not shown) as a sharp light beam 35 from the light emitting surface 34.

As shown in FIG. 4, in the optical semiconductor device 30, the lead frame 10 is integrally molded with a resin 40.
As shown in FIG. 5, when the lead frame 10 is molded with the resin 40, the resin 40 penetrates into the gap 41 between the side 12 a of the mount head 12 and the side 15 a of the convex portion 15 from the upper side and the lower side of the lead frame 10. The resin 40 that has penetrated is united with each other to be solidified and integrated.

  As a result, the integrated resin 40 acts as a virtual anchor 42 that bites into the gap 41 between the side 12a of the mount head 12 and the side 15a of the convex portion 15 as indicated by a broken line. It is possible to prevent the resin 40 from being peeled from the lead frame 10 due to the difference in thermal expansion of 40.

  According to the stress simulation, after the reflow process at the heating temperature of 245 ° C., the deformation amount of the lead frame is reduced to ½ or less, and the contact area between the lead frame 10 and the resin 40 is 70 when the convex portion 15 is not provided. It was about 90%, but it was about 90% when the convex portion 15 was provided, indicating an improvement of about 20%.

  This anchor effect varies depending on the distance L1 between the side 12a of the mount head 12 and the side 15a of the convex portion 15 and the opposing length L2.

  For example, if the separation distance L1 is too small, the penetration of the resin becomes non-uniform and the anchor effect is lowered, and if the separation distance L1 is too large, the thermal stress of the resin becomes excessive and the anchor effect is reduced. Therefore, as described above, about three times the thickness of the lead frame is appropriate and preferable.

  Furthermore, since the anchor effect is increased by increasing the opposing length L2 while keeping the separation distance L1 optimal, the opposing length L2 is preferably as large as possible within a range of ¼ or less of the outer peripheral length of the mount head 12. .

  As described above, according to the present embodiment, the convex portion 15 of the third lead terminal 16 is brought close to the outer periphery of the mount head 12, and the side 12a and the side 15a facing each other along a part of the outer periphery are provided. Therefore, the resin 40 is fixed to the lead frame 10 by the anchor effect of the resin 40 penetrating into the gap 41 between the sides 12a and 15a.

  As a result, even if there is a difference in thermal expansion between the resin and the lead frame in the reflow process, the resin can be prevented from peeling from the lead frame.

  Here, the case where the base portion 32 and the lens portion 33 of the package 31 are integrally formed has been described, but the base portion and the lens portion may be formed separately.

  FIG. 6 is a plan view showing a lead frame according to Embodiment 2 of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different portions will be described.

  This embodiment differs from the first embodiment in that the shape of the mount head is circular and the shape of the convex portion of the third lead terminal is matched to the circumference of the mount head.

  That is, as shown in FIG. 6, the lead frame 50 of this embodiment is provided with a circular mount head 52 and a space away from the mount head 52, and the mount head is in the first direction or the second direction. And a third lead terminal 56 having an arcuate convex portion 15 in the direction in which 52 is provided.

  The convex portion 55 of the third lead terminal 56 has an arc 55 a that is spaced apart and opposed along the circumferential arc 52 a of the mount head 52.

  The distance L3 between the arc 52a of the mount head 52 and the arc 55a of the convex portion 15 is set to, for example, about three times the thickness of the lead frame 50 and about 0.45 mm, and the length L4 of the arc 55a of the convex portion 55 is set. Is set to about the length of the arc 52a of the mount head 52, for example.

  Thereby, since the length L4 of the arc 55a of the convex portion 55 can be made larger than the length L2 of the side 15a of the convex portion 15, the anchor effect is increased even when the separation distance L1 and the separation distance L3 are the same. Is possible.

  As described above, according to the present embodiment, when the length L4 of the arc 55a of the convex portion 55 is larger than the length L2 of the side 15a of the convex portion 15, the separation distance L1 and the separation distance L3 are the same. However, there is an advantage that the anchor effect can be increased.

  FIG. 7 is a plan view showing a lead frame according to Embodiment 3 of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different portions will be described.

  The present embodiment is different from the first embodiment in that the convex portions and the third lead terminals are arranged substantially linearly.

  That is, as shown in FIG. 7, in the lead frame 60 of this embodiment, the convex portion 65 and the third lead terminal 66 are arranged in a substantially linear shape, and the third lead terminal 66 is further connected to the lead terminals 21, 22, 24. , 25 are arranged substantially linearly.

  Since the convex portion 65 is arranged substantially linearly with the third lead terminal 66, when the lead frame 60 is formed by pressing the copper plate, the convex portion 65 becomes difficult to deform, and the mount head 12 and the convex portion are formed. Since the variation in the separation distance L1 of 65 is prevented, there is an advantage that the adhesion between the lead frame 60 and the resin 40 is improved.

  Further, since the third lead terminal 66 is arranged substantially linearly with each of the lead terminals 21, 22, 24, and 25, the number of irregularities in the press working pattern is reduced, and the press working die can be easily manufactured. There is.

  As described above, according to this embodiment, since the variation in the separation distance L1 between the mount head 12 and the convex portion 65 is prevented, there is an advantage that the adhesion between the lead frame 60 and the resin 40 is improved.

  In the embodiment described above, the case where the third lead terminal is provided on both sides of the first lead terminal and on both sides of the second lead terminal has been described, but the present invention is not limited to this, and the lead frame is not limited thereto. As long as the required adhesion between the resin and the resin is obtained, the position and number of the resin may be appropriately changed.

  Further, the case where the outer periphery of the mount head and the convex portion of the third lead terminal are spaced apart and substantially parallel to each other has been described. However, as long as the necessary adhesion between the lead frame and the resin is obtained, it is appropriately selected. You can change it.

FIG. 1A is a plan view of a lead frame according to Embodiment 1 of the present invention, FIG. 1B is a cross-sectional view taken along line AA in FIG. A cross-sectional view. 1 is a perspective view showing a state in which a lead frame according to Embodiment 1 of the present invention is used. 1 is a perspective view of the inside of an optical semiconductor device according to Embodiment 1 of the present invention seen through. FIG. Sectional drawing which shows the optical semiconductor device which concerns on Example 1 of this invention. The figure which shows typically the contact | adherence state of the lead frame and resin which concern on Example 1 of this invention. The top view which shows the lead frame which concerns on Example 2 of this invention. The top view which shows the lead frame which concerns on Example 3 of this invention.

Explanation of symbols

10, 50, 60 Lead frame 11 Reflecting plate portion 12, 52 Mount head 13 First lead terminal (cathode)
14 Second lead terminal (anode)
15, 55, 65 Convex parts 16, 56, 66 Third lead terminal 17 Inner bottom part 18, 31 Package 20, 23 Connecting bar 21, 22, 24, 25 Lead terminal 27 Optical semiconductor element 28 Wire 29 Bonding part 30 Optical semiconductor device 32 Base part 33 Lens part 34 Light emitting surface 35 Light beam 40 Resin 41 Crevice 42 Anchor

Claims (5)

A mount head having a reflector portion;
A first lead terminal extending in a first direction from the mount head;
A second lead terminal provided apart from the mount head and extending from the mount head in a second direction opposite to the first direction;
A third lead terminal provided apart from the mount head and having a convex portion in the first direction or the second direction and in which the mount head is provided;
A lead frame comprising:   The lead frame according to claim 1, wherein the third lead terminal is provided on both sides of the first lead terminal and on both sides of the second lead terminal.   3. The lead frame according to claim 1, wherein a separation distance between the mount head and the convex portion is 2.5 to 3.5 times a thickness of the lead frame.   4. The lead frame according to claim 1, wherein an opposing length of the mount head and the convex portion is ¼ or less of an outer peripheral length of the mount head. 5. A mount head having a reflector portion;
A first lead terminal extending in a first direction from the mount head;
A second lead terminal provided apart from the mount head and extending from the mount head in a second direction opposite to the first direction;
A third lead terminal provided apart from the mount head and having a convex portion in the first direction or the second direction and in which the mount head is provided;
A lead frame with
An optical semiconductor element mounted on the inner bottom of the reflector,
A connection conductor for electrically connecting the optical semiconductor element to the second lead terminal;
A package in which the lead frame and the optical semiconductor element are molded;
An optical semiconductor device comprising:

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