JP5684631B2 - LED package substrate - Google Patents

Description

  The present invention relates to an LED package substrate in which a resin is molded on a lead frame.

  Conventionally, as disclosed in Patent Document 1, there is an LED package including an LED chip that emits light of a predetermined wavelength. Such an LED package is manufactured by mounting a plurality of LED chips on a lead frame to form an LED package substrate, and cutting the LED package substrate into individual pieces.

  In Patent Document 1, a reflector formed by a primary molding resin (white resin) by transfer molding is provided so as to surround each of a plurality of LED chips on a lead frame. The plurality of LED chips are sealed with a secondary molding resin (transparent resin) having a function as a lens portion.

JP 2010-182770 A

  In the LED package disclosed in Patent Document 1, when a primary molding resin or a secondary molding resin is molded on a lead frame by transfer molding, an unnecessary molding is performed on the runner / gate portion immediately after molding each resin. A degate process for removing the resin is required. However, when unnecessary resin is removed in the degate process, among the resin molded on the lead frame, there is a possibility that resin that should not be removed in the region near the runner / gate is also peeled off at the same time.

  Therefore, the present invention provides an LED package substrate in which the adhesion strength of a resin molded on a lead frame is improved.

An LED package substrate according to an aspect of the present invention is an LED package substrate used for manufacturing an LED package, a die pad for electrical connection to a first electrode of an LED chip, and the LED A lead frame having a lead for electrical connection to the second electrode of the chip, and a hole formed between the die pad and the lead is filled by transfer molding, and is molded on the surface of the lead frame. and a first resin, an end portion on the surface of the previous SL lead frame, the lead frame the first is disposed on the outer periphery of the inner resin said first resin molded on the surface of the the first groove is filled with, and, second filling said first be a arranged outside of the resin the LED chips molded on the surface of the lead frame Resins and a second groove which is to be filled is formed by the second groove is on said surface of said lead frame, an outer of said first groove, and, It is formed at a position between a pair of adjacent gates among a plurality of gates of a mold used in the transfer molding of the first resin .

  Other objects and features of the present invention are illustrated in the following examples.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate for LED packages which improved the adhesive strength of resin shape | molded on the lead frame can be provided.

In Example 1, it is a top view of the board | substrate for LED packages after (a) lead frame and (b) primary shaping | molding. It is a schematic sectional drawing of the metal mold | die used for the primary shaping | molding in Example 1, (a) Before resin sealing, (b) It is the state after resin sealing. FIG. 3 is a cross-sectional view of the LED package substrate according to the first embodiment at the time of degate. It is a schematic sectional drawing of the metal mold | die used for the secondary shaping | molding in Example 1, (a) Before resin sealing, (b) It is the state after resin sealing. 3 is a plan view of the LED package substrate after secondary molding in Example 1. FIG. 7 is a plan view of a lead frame in Embodiment 2. FIG. 10 is a modification of the lead frame in Embodiment 2.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  First, with reference to FIG. 1 thru | or FIG. 5, the board | substrate for LED packages in Example 1 of this invention is demonstrated. FIG. 1 is a plan view of a lead frame 10 (FIG. 1A) and an LED package substrate (FIG. 1B) in the present embodiment. The LED package substrate of the present embodiment is used to manufacture an LED package as a final product, and is configured such that a plurality of LED chips are mounted on or can be mounted on a resin-molded lead frame 10. Yes.

  The lead frame 10 is configured, for example, by forming a plating layer (for example, Ni-Ag plating) made of nickel, palladium, silver, gold, or the like on the surface of a copper-based frame material. The plate thickness of the lead frame 10 is, for example, 0.5 mm, and a lead frame having a plate thickness of about 0.2 mm or 0.3 mm may be used. As will be described later, a plurality of LED chips are mounted on the lead frame 10 after sealing the resin for the reflector, and a dicing (separation) process for cutting the lead frame 10 after sealing the resin for the lens is performed. Thus, a plurality of LED packages as final products are completed.

  The lead frame 10 includes a die pad 12 (base-side lead) configured to be electrically connected to a first electrode (anode electrode) of an LED chip described later. The lead frame 10 includes a lead 13 (terminal-side lead) configured to be electrically connected to a second electrode (cathode electrode) different from the first electrode of the LED chip. The LED chip is mounted on the die pad 12. A punching hole 16 is provided around the die pad 12 and the lead 13 (between the die pad 12 and the lead 13), and the die pad 12 and the lead 13 are separated from each other. In the present embodiment, the pad portion 14 is constituted by the die pad 12 and the lead 13. Note that the present embodiment is not limited to this, and conversely to the above configuration, the cathode electrode of the LED chip may be connected to the die pad 12 and the anode electrode may be connected to the lead 13. .

  As shown in FIG. 1A, the lead frame 10 of the present embodiment is composed of a plurality of pad portions 14 (unit elements). In the range of the lead frame 10 shown in FIG. A total of 30 LED packages of 5 vertical and 6 horizontal are produced.

  Further, the lead frame 10 is provided with a plurality of concave grooves 20 (half-etched portions) formed by half-etching at the end portion on the surface where the runner / gate (region 155) at the time of transfer molding is disposed. ing. The plurality of grooves 20 are formed side by side on the lead frame 10. Similarly, a plurality of concave grooves 30 (half-etched portions) formed by half etching are provided on the surface of the lead frame 10 outside the plural concave grooves 20. The plurality of concave grooves 30 are also formed side by side on the lead frame 10.

  As will be described later, the concave groove 20 (first concave groove) is filled with the primary molding resin (white resin), and the concave groove 30 (second concave groove) is filled with the secondary molding resin (transparent resin). . The concave grooves 20 and 30 are anchor effects that suppress the separation of the resin from the lead frame 10 during the delegation step of each of the primary molding resin and the secondary molding resin (step of removing the runner / gate immediately after resin molding). Is provided for.

  As shown in FIG. 1B, the resin 71 as the primary molding resin is transfer molded to the lead frame 10 to form a rectangular shape that collectively seals the hole 16 that forms the pad portion 14. A package is formed on the lead frame 10. The resin 71 forms a reflector 72 on the surface of the lead frame 10 so as to surround the LED chip mounting region 18. As described above, in this embodiment, a map type LED package substrate in which the reflectors 72 of all the LED chip mounting regions 18 in the lead frame 10 are integrally formed of the resin 71 is manufactured. However, the present invention is not limited to this, and can be applied to a matrix type LED package substrate.

  Next, a mold used when the lead frame 10 in this embodiment is resin-sealed with a primary molding resin will be described. FIG. 2 is a schematic cross-sectional view of a mold used for primary molding in the present embodiment, and shows a state in which a lead frame is clamped by the mold. FIG. 2A is a state before resin sealing, and shows a cross section cut along a line AA in FIG. FIG. 2B is a state after resin sealing, and shows a cross section cut along a line BB in FIG. In these drawings, the same structure is arranged on the left side of the alternate long and short dash line, so that the two lead frames 10 are resin-sealed by one molding.

  As shown in FIGS. 2A and 2B, in this embodiment, the mold used at the time of primary molding is configured to include an upper mold 50 and a lower mold 60. The upper mold 50 includes upper mold inserts 51a and 51b and a center insert 53. The upper mold insert 51a is provided with a plurality of convex portions 52 that are provided at the same interval as the pad portion 14 and project. The plurality of convex portions 52 are surrounded by a rectangular cavity 57. With such a configuration, the upper mold 50 determines the shape of the resin 71 (primary molding resin) to be filled in the lead frame 10.

  The inside of the cavity 57 of the upper mold insert 51 is filled with resin when the lead frame 10 is resin-sealed by transfer molding. The resin filled in the cavity 57 forms a reflector that reflects light from the LED chip described later. In the vicinity of the gate 56 inside the cavity 57, a plurality of concave grooves 20 are formed on the lead frame 10. For this reason, the inside of these concave grooves 20 is also filled with resin. Further, the plurality of convex portions 52 serve as a clamp surface (LED chip mounting region 18) for clamping the pad portion 14 of the lead frame 10.

  The center insert 53 is formed with a part of the cull 55 and the runner 54, which communicate with the other part of the runner 54 formed on the upper mold insert 51 and the gate 56. The upper mold 50 presses the lead frame 10 from the upper surface side so that the pad portion 14 (the die pad 12 and the lead 13) and the cavities 57 and 57a overlap each other at the time of resin sealing.

  The lower mold 60 includes a lower mold insert 61, and the lead frame 10 is disposed on the planar lower mold insert 61. The lower mold 60 presses the lead frame 10 from the lower surface side during resin sealing.

  As described above, the mold of this embodiment is mainly composed of the upper mold 50 and the lower mold 60. At the time of resin sealing (resin molding), the lead frame 10 is clamped (sandwiched) by the upper mold 50 and the lower mold 60, and the resin as the primary molding resin is placed inside the cavities 57, 57a and the punch hole 16. 71 (resin for reflector) is filled.

  Reference numeral 70 denotes a resin tablet obtained by molding a thermosetting resin or the like into a tablet (column) shape. At the time of resin sealing, as shown in FIG. 2A, the pot 63 inserted in the pot insert 62 of the lower mold 60 is preheated, and the resin tablet 70 is put into the pot 63 and melted. Then, as shown in FIG. 2B, the molten resin 71 is pumped by moving the plunger 64 configured to be slidable up and down along the pot 63 by a transfer mechanism (not shown). The space between the upper mold 50 and the lower mold 60 is filled with the resin 71. Instead of the resin tablet 70, a liquid thermosetting resin can be supplied by a dispenser (not shown). Further, granular, granular or gel resins can be used.

  When the resin 71 is pumped by the plunger 64, the molten resin 71 is supplied to the punch hole 16 and the cavity 57 (concave groove 20) through the cull 55, the runner 54, and the gate 56. That is, the resin 71 is sequentially supplied from the punch hole 16 and the cavity 57 (concave groove 20) close to the gate 56 toward the punch hole 16 and the cavity 57 far from (distant from) the gate 56. In this way, the resin tablet 70 is melted to become the resin 71 and is injected into the space formed by the upper mold 50 and the lower mold 60. As a result, as shown in FIG. 2B, the space between the upper mold 50 and the lower mold 60 (specifically, the cavity 57 (concave groove 20) and the punched hole 16) is made by the resin 71. Filled state.

  After the resin 71 is filled, the resin 71 waits for a predetermined time to cure the resin 71, and the upper mold 50 and the lower mold 60 are closed. Next, after the resin-molded LED package substrate is unloaded, the parting surface of the mold is cleaned, and one resin molding step is completed. After the above steps, the LED package substrate of this embodiment is formed as shown in FIG.

  The resin 71 (white resin) as the primary molding resin is a thermosetting resin made of a silicone resin or an epoxy resin containing white powder such as titanium oxide or alumina and silica. As described above, the upper package is integrally formed on the lead frame 10 by pouring and curing the resin 71 by transfer molding. As described above, the LED package substrate in the present embodiment is a map type LED package substrate that is molded together with the resin 71.

  Further, the resin 71 forms a reflector 72 that reflects upward light emitted from an LED chip described later. The resin 71 also has a function of improving the strength of the LED package. However, the resin 71 is not formed in a predetermined region (LED chip mounting region 18) on the lead frame 10 in which LED chips to be described later are mounted in a plurality of regions by being clamped by the convex portions 52. The LED chip mounting area 18 is an area where the surface of the lead frame 10 is exposed after the primary molding.

  FIG. 3 is a cross-sectional view of the lead frame 10 (LED package substrate) after being filled with the primary molding resin (resin 71), and shows a state at the time of delegation. As shown in FIG. 3, in order to remove the resin 71 filled in the runner / gate from the LED package substrate, it is necessary to cut (twist) the excess resin 71. In the present embodiment, the groove 20 (half-etched portion) is provided in the vicinity of the runner / gate, and the resin 71 is filled in the groove 20. For this reason, the area where the resin 71 is in close contact with the lead frame 10 is increased, and it is possible to effectively suppress the separation of the resin at the time of delegation.

  Next, the metal mold | die used when resin-sealing the board | substrate for LED packages in a present Example with secondary molding resin is demonstrated. FIG. 4 is a schematic cross-sectional view of a mold used for secondary molding in the present embodiment, and shows a state in which the LED package substrate is clamped with the mold. FIG. 4A shows a state before resin sealing, and FIG. 4B shows a state after resin sealing. In these figures, the same configuration is arranged on the left side of the alternate long and short dash line, so that two LED package substrates are resin-sealed by one molding. FIG. 5 is a plan view of the LED package substrate after the secondary molding. A cross section taken along line BB in FIG. 5 corresponds to FIG.

  As shown in FIGS. 4 and 5, an LED chip 40 (semiconductor chip) is mounted on the lead frame 10 (LED package substrate) after the primary molding. Secondary molding in the present embodiment is performed after the LED chip 40 is mounted on the lead frame 10.

  As shown in FIGS. 4A and 4B, in this embodiment, the mold used at the time of secondary molding includes an upper mold 80 and a lower mold 90. The upper mold 80 includes upper mold inserts 81 a and 81 b and a center insert 83. A rectangular cavity 87 is provided in the upper mold inserts 81a and 81b. A plurality of hemispherical concave portions 89 are provided in the cavity 87 at the same interval as the pad portion 14. With such a configuration, the upper mold 80 determines the shape of the resin 76 (secondary molding resin) filled in the lead frame 10.

  The cavity 87 (concave portion 89) of the upper mold insert 81 is filled with a resin 76 as a secondary molding resin by transfer molding. The resin portion 76 is filled in the concave portion 89, whereby the lens portion 79 of the LED package is formed. A plurality of concave grooves 30 are formed on the lead frame 10 near the gate 86 inside the cavity 87 (on the left side of the concave groove 20 in FIG. 4). For this reason, the inside of these concave grooves 30 is also filled with the resin 76. As described above, in this embodiment, as shown in FIGS. 1 and 5, since the concave grooves 20 and 30 are arranged so as to avoid the front of the gate, the flow of the resins 71 and 76 in the cavities 57 and 87 is caused. The resin is smoothly filled without being disturbed.

  The center insert 83 is formed with a part of the cull 85 and the runner 84 as in the case of the upper mold 50 used in the primary molding, and these are other parts of the runner 84 formed on the upper mold insert 81. And a gate 86. The upper mold 80 presses the lead frame 10 from the upper surface side so that the concave portion 89 and the LED chip 40 (LED chip mounting region 18) overlap each other at the time of resin sealing.

  The lower mold 90 is configured to include a lower mold insert 91 in the same manner as the lower mold 60 used during primary molding, and the lead frame 10 is disposed on the planar lower mold insert 91. The lower mold 90 presses the lead frame 10 from the lower surface side during resin sealing.

  As described above, the mold of this embodiment is mainly composed of the upper mold 80 and the lower mold 90. At the time of resin sealing (resin molding), the lead frame 10 is clamped (sandwiched) between the upper mold 80 and the lower mold 90, and is secondary to the cavity 87, the concave groove 30, and the plurality of concave portions 89. A resin 76 (lens resin) as a molding resin is filled by transfer molding. As a result, the LED chip 40 is filled with the resin 76.

  In FIG. 4A, reference numeral 75 denotes a resin tablet obtained by molding a thermosetting resin or the like into a tablet (column) shape. As in the case of the above-described resin tablet 70, the pot 93 inserted into the pot insert 92 of the lower mold 90 is preheated, and the resin tablet 75 is put therein and melted. Then, as shown in FIG. 4B, the molten resin 76 is pumped by moving a plunger 94 configured to be slidable up and down along the pot 93 by a transfer mechanism (not shown). The space between the upper mold 80 and the lower mold 90 is filled with the resin 76.

  As the resin 76 is pumped by the plunger 94, the melted resin 76 passes through the cull 85, the runner 84, and the gate 86 (runner / gate shown by the region 185 in FIG. 5) as shown in FIG. To the cavity 87 (the recessed groove 30 and the recessed portion 89). As a result, as shown in FIG. 4B, the space between the upper mold 80 and the lower mold 90 is filled with the resin 76.

  The resin 76 as the secondary molding resin is a transparent resin, and for example, a translucent silicone resin is used. Silicone resin has durability against discoloration or deterioration due to light or heat when the emission wavelength of LED chip 40 is a short wavelength such as blue light or when the LED chip is a high-brightness LED and generates a large amount of heat. Is excellent. However, the resin 76 as the secondary molding resin is not limited to the silicone resin, and a thermosetting resin having translucency such as an epoxy resin, a urethane resin, or an acrylic resin may be employed.

  Regarding the secondary molding resin (resin 76) as well as the primary molding resin (resin 71), in order to remove the resin 76 filled in the runner / gate from the LED package substrate, the excess resin 76 is cut (twisted). There is a need to. In this embodiment, the groove 30 (half-etched portion) is provided in the vicinity of the runner / gate, and the inside of the groove 30 is filled with resin 76. For this reason, the area where the resin 76 is in close contact with the lead frame 10 is increased, and it is possible to effectively suppress the peeling of the resin at the time of degate.

  Next, an LED package substrate (lead frame) according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 6 is a plan view of the lead frame 10a (FIG. 6A) and the LED package substrate (FIG. 6B) in the present embodiment.

  In the lead frame 10a of the present embodiment, one long concave groove 20a (half-etched portion) is integrally formed on one side in the vicinity of the runner / gate indicated by the region 155 in FIG. This is different from the lead frame 10 of the first embodiment in which a plurality of concave grooves 20 are formed. Even if such a configuration is adopted as the primary molding concave groove (first concave groove), it is possible to effectively suppress resin peeling at the time of delegation. In this case, since the concave groove 20 is formed in front of the runner / gate, the resin peeling at the time of degate can be more effectively suppressed. However, when supplying resin for primary molding and secondary molding from the same side of the lead frame 10a, the concave groove for secondary molding (second concave groove) is the position of the runner / gate at the time of primary molding. Therefore, it cannot be formed integrally. Therefore, when the primary molding resin and the secondary molding resin are supplied from the other side of the lead frame 10a, the secondary molding concave groove (second concave groove) can be integrally formed. In this case, it is particularly effective when using a resin that is flexible and difficult to degate, such as a liquid silicone resin for lenses.

  Subsequently, a modification of the lead frame in the present embodiment will be described. FIG. 7 is a plan view of an essential part showing a modified example of the lead frame, and shows a configuration of a concave groove for primary molding. FIG. 7A shows a concave groove 20b having a configuration in which both end portions protrude to the concave groove 30 side. FIG. 7B shows a concave groove 20c having a plurality of oval shapes. FIG. 7D shows a concave groove 20d having a bent portion (zigzag portion). By adopting the concave grooves as shown in FIGS. 7A to 7C, the surface where the concave grooves come into contact with the resin increases, so that the anchor effect can be improved.

  According to each of the above embodiments, it is possible to provide an LED package substrate in which the adhesion strength of the resin molded on the lead frame is improved.

  The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the matters described as the above-described embodiments, and can be appropriately changed without departing from the technical idea of the present invention.

  For example, in each of the above embodiments, the concave groove is formed in order to improve the adhesion strength of the resin, but the same effect can be obtained by forming a through hole instead of the concave groove.

10, 10a Lead frame 12 Die pad 13 Lead 14 Pad part 16 Punch hole 18 LED chip mounting area 20, 30 Recess groove 40 LED chip 50, 80 Upper mold 51, 81 Upper mold insert 60, 90 Lower mold 61, 91 Lower Mold insert 71, 76 Resin

Claims (6)

An LED package substrate used for manufacturing an LED package,
A die pad for electrical connection to the first electrode of the LED chip, and a lead frame comprising leads for electrical connection to the second electrode of the LED chip;
Filled into vent hole between the die pad and the lead by transfer molding, and the first resin molded on the surface of the lead frame,
At the end of the on the surface of the previous SL lead frame, the first filled with the lead frame first is a disposed on the outer peripheral portion of the inner resin said first resin molded on the surface of the A concave groove and a second concave groove that is disposed outside the first resin molded on the surface of the lead frame and is filled with the second resin that fills the LED chip are formed. Has been
The second concave groove is formed on the surface of the lead frame, outside the first concave groove, and in a plurality of molds used in the transfer molding of the first resin. A substrate for an LED package, which is formed at a position between a pair of adjacent gates among gates . The second groove is a plurality of grooves formed on one side of the lead frame,
2. The LED package substrate according to claim 1, wherein each of the plurality of concave grooves is formed at a position between the pair of adjacent gates. The first groove is, LED package substrate according to claim 1 or 2, characterized in that said a plurality of grooves formed on one side of the lead frame. 3. The LED package substrate according to claim 1, wherein the first groove is a single groove formed integrally on one side of the lead frame. 4. It said LED chip mounted on the lead frame,
LED package substrate according to any one of claims 1 to 4, the transparent resin as the second resin filling the LED chip by transfer molding, and further perforated to said Rukoto a. Said first groove and said second groove is, LED package substrate according to any one of claims 1 to 5, characterized in that it is formed by half etching of said lead frame.