JP2013030561A - Lead frame, molding die, semiconductor device, and package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure air to be blown out from a cavity of a molding die to the exterior thereby preventing the occurrence of molding defects due to insufficient resin filling and improving the yield when a package of a semiconductor device is molded.SOLUTION: When a package 2, integrated with a resin molding by installing a lead frame 1 having a terminal lead 13 in a molding die and performing the resin mold, is molded, multiple hanging leads 14, 14 each of which connects with and supports a peripheral part of the resin molding, are provided at the lead frame 1. Multiple vent grooves 14a are formed on surfaces of the hanging leads 14, 14 to blow out air in a cavity from the vent grooves 14a to the exterior.

Description

  The present invention mainly relates to a lead frame structure of a package on which a light emitting element is mounted, a molding die for molding the package, a package molded by these, and a semiconductor device.

  A semiconductor device in which a semiconductor element is sealed in a package shown in FIG. 12 has a semiconductor element 102 mounted on a tab (die pad) 101 of a lead frame 100, and the electrode of the semiconductor element 102 and an inner lead are wire-bonded. After the connection, the package 103 is formed by resin molding with a mold, and the lead frame is cut together with the resin burr formed around the package 103, and the outer lead 104 is bent together.

In the molding process of the package of such a semiconductor device, the mold die is usually provided with an air vent portion at the corner other than the gate for sending the air remaining in the cavity to the outside. For this reason, the sealing resin adheres and is easily clogged, and the air in the cavity is not sufficiently sent to the outside, and the injection of the sealing resin is insufficient and may cause insufficient filling.
As a means for solving this, as shown in the figure, an air vent portion 105 is provided in the outer lead 104 and the tab suspension lead of the lead frame 100, and the air in the cavity of the mold dies passes through the air vent portion 105 to the outside of the cavity. The thing of the structure made to send out is known (for example, refer patent document 1, 2).

JP-A-7-111305 Japanese Patent Laid-Open No. 11-220087

  Among surface-mount type optical semiconductor devices equipped with light-emitting elements such as LD elements used in optical fiber communications and LED elements used in LED lamps, the type of package whose leads are exposed from the two sides and bottom of the package In addition, a product that is integrally formed on a lead frame using a resin material such as a thermosetting resin having excellent reflection characteristics and heat resistance has been commercialized.

In such a package, if a material with low viscosity and good molding fluidity is used, such as a thermosetting resin, the resin flows into the gaps in the molding die, and burrs and resin covering are easily formed. Resin that adheres to the air vent part and hardens in combination with the fact that it flows easily into the air vent part formed at the periphery of the molding die for sending out to the outside and easily clogs, and the resin hardens quickly and the solidification time is short. Therefore, there is a problem in molding technology that the air in the cavity is not sufficiently sent to the outside, and the resin is easily filled due to the air pool.
In this case, even if the air vent portion is provided in the portion of the lead frame that is loaded in the cavity of the lead frame, like the outer lead or the tab suspension lead sealed in the resin in the prior art, the molding fluidity However, it is inevitable that a good resin will flow into the air vent part and solidify and become clogged, and the air pool in the cavity will cause insufficient filling of the resin. In particular, the prior art cannot be applied to an embodiment in which the type of package is formed using a resin material having a low viscosity such as a silicone resin among thermosetting resins.

The package includes a step of attaching a light emitting element in a state in which a suspension lead is connected to a peripheral portion of the package and is integrally formed with the lead frame and supported in the lead frame via the suspension lead. The semiconductor device is processed into a semiconductor device through a step of connecting the terminal lead and the electrode of the light emitting element with a wire and a step of covering the portion connected with the light emitting element with the wire with a protective resin. The connecting portion is divided and removed from the lead frame, and attached to the circuit board of the electronic device.
Therefore, while processing from a package to a semiconductor device, it is necessary to fix the package to the lead frame so that the package cannot be removed. Especially, silicone resin has low viscosity and is soft after curing, so the connection between the package and the suspension lead The portion was fragile and the package was easily removed from the lead frame, and scrap was easily generated from the connecting portion of the package and the suspension lead when the package was removed from the lead frame.

  In view of these problems of the prior art, the present invention prevents the occurrence of molding defects due to insufficient filling of the resin by reliably sending air out of the mold cavity when molding the package of the semiconductor device. It is therefore an object of the present invention to improve the yield and to ensure that the package is securely held by the lead frame in the process of processing the package into a semiconductor device.

  In order to solve the above-mentioned problems, the present invention provides a lead frame having a die pad on which a semiconductor element is mounted and a terminal lead constituting an electrode, and is placed in a molding die to perform resin molding, thereby forming the die pad and the terminal lead. The lead frame for forming a package in which the resin molded body is integrated is provided with a plurality of suspension leads that are connected to and supported by the peripheral portion of the resin molded body, and at least one of the plurality of suspension leads. A vent groove is formed on the surface of one suspension lead.

According to this, by providing the vent groove on the surface of the suspension lead, the air in the cavity of the molding die can be sent out from the vent groove to the outside of the molding die at the time of molding the package. Even if no vent groove is provided in the air, it is possible to effectively prevent air from being accumulated in the cavity.
In addition, by providing a vent groove in the suspension lead, even if the resin flows into the vent groove during clogging and becomes clogged and the venting effect is lost, the resin does not adhere to the molding die and the next package molding In this case, molding is performed on a new lead frame that does not have resin attached to the vent groove. Therefore, the lead frame is installed in the molding die sequentially without causing insufficient resin filling. Can be molded.
Furthermore, by providing a vent groove in the lead of the lead frame, after forming the package or processing the package into a semiconductor device, the terminal lead of the lead frame is cut and the package is removed from the lead frame into individual pieces. The suspension leads are also separated from the package and no vent groove is left in the package, so that the function and appearance of the package are not hindered.

In the lead frame configured as described above, it is preferable that the surface of the vent groove is subjected to a roughing process for increasing the frictional resistance.
If the surface of the vent groove is rougher than the surface of the molding die, the resin burrs generated during the molding of the package will not adhere to the vent groove and remain in the molding die. The roughing process is a process for increasing the frictional resistance than the surface of the molding die by providing a concave groove, a convex line, an uneven part, etc. on the surface of the vent groove. Can be performed simultaneously with the formation of or after the formation of the vent groove. Usually, when the vent groove is formed by the pressing die simultaneously with the punching of the lead frame, fine irregularities and streaks are formed on the surface of the vent groove, and the frictional resistance is increased.

In the lead frame having the above-described configuration, it is preferable that a tip portion of the suspension lead is provided with a tapered portion inclined from the top surface tip side of the lead to the bottom surface base side.
According to this, by providing a tapered portion at the tip of the suspension lead and connecting it to the periphery of the package, the package is stably supported in the lead frame via the suspension lead, and the suspension lead When separating the package from the package, the tip of the suspension lead can be easily removed from the periphery of the package, and no debris is produced from the portion connected to the package.

The molding die of the present invention is a molding die for integrally forming a resin molded body on the lead frame having the above-described structure, and the position of the gate for flowing the resin into the cavity is the suspension lead is the resin. It is arrange | positioned so that it may become a filling terminal part.
According to this, by arranging the position of the gate, which is a resin inflow port necessary for the molding of the package, as described above, an air reservoir that is likely to be generated in the filling terminal portion in the cavity is passed through the vent groove of the suspension lead. It can be efficiently discharged outside the molding die.

The molding die of the present invention is a molding die for integrally forming a resin molding on the lead frame having the above-described configuration, and the upper die and the lower die constituting the molding die are arranged in the upper and lower sides. It is characterized in that it is provided so as to be sandwiched and press-contacted with the edge of the lead and the suspension lead of the lead frame installed between the molds.
The lead frame is formed by punching and pressing a steel plate, and “sag” is formed at the edge of the punched frame. As described above, the edge of the lead frame terminal lead and the suspension lead are connected with the upper and lower molds. By forcibly sandwiching and press-contacting, the “sagging” edge is deformed, and the adhesion between the lead frame and the joint of the package can be improved.

According to another aspect of the present invention, there is provided a semiconductor device in which a semiconductor element is mounted on the lead frame having the above-described configuration, the electrical terminals of the semiconductor element and the terminal leads of the lead frame are electrically connected, and the semiconductor element is covered with a resin. It is formed.
In this case, the semiconductor device mounts the semiconductor element on the lead frame, electrically connects the electrode terminal and signal terminal of the semiconductor element to the terminal lead of the lead frame with a wire or the like, and attaches the lead frame on which the semiconductor element is mounted. It can be formed by setting in a molding die, filling the cavity with resin and curing it, and performing molding to cover the periphery of the semiconductor element with resin.
As described above, even when the semiconductor device is formed by molding, it is difficult for the air in the cavity of the molding die to be sent out from the vent groove of the lead frame to the outside of the molding die, and it is difficult to collect air in the cavity. Occurrence of molding defects due to insufficient filling can be effectively prevented.

The package of the present invention is formed using the lead frame or the molding die having the above-described configuration.
Furthermore, the light emitting device of the present invention mounts a semiconductor element on the package, electrically connects the electrode portion of the light emitting element and the terminal lead of the lead frame, and seals the light emitting element mounted in the package. It is formed by covering with a stopper. As the sealing material, a light-transmitting sealing material, a sealing material made of an epoxy-based resin or silicone, a resin in which an inorganic filler is blended, or the like can be used.

  The lead frame, molding die, and package of the present invention can be used for manufacturing a light receiving device in which a light receiving element is mounted and other semiconductor devices in addition to a light emitting device in which a light emitting element is mounted. is there.

FIG. 4 is a top view (A) and a bottom view (B) of a state in which a package is formed on the lead frame of one embodiment of the present invention. FIG. 2 is a top view (A) and a bottom view (B) of the lead frame in FIG. 1. FIG. 3 is an enlarged end view taken along line III-III in FIG. 2. FIG. 2 is a schematic cross-sectional view of a molding die showing a position of a tip end portion of a suspension lead in a state where a lead frame is installed in a molding die for molding the package of FIG. 1. FIG. 5 is a schematic cross-sectional view of a molding die showing the position of a pair of suspension leads as in FIG. 4. It is the figure which showed the flow of air and resin when resin flows in into the cavity of the shaping die shown in FIG. FIG. 2 is an external view of a state in which the LED element is mounted by removing the package of FIG. 1 from the lead frame. FIG. 6 is a top view (A), a bottom view (B), and a sectional view (C) of a vent groove in a state where a package is formed on a lead frame of another embodiment of the present invention. FIG. 9 is a top view (A) and a bottom view (B) of a state in which a package is formed on a lead frame according to still another embodiment of the present invention. It is a schematic sectional drawing of the shaping die in the state where the lead frame of other forms from which the end part shape of a suspension lead differs was installed in the shaping die. It is a schematic sectional drawing of the shaping die in the state where the lead frame of another form from which the end shape of a suspension lead differs is installed in the shaping die. It is a schematic sectional drawing of an example of the conventional semiconductor device.

Preferred embodiments of the present invention will be described with reference to the drawings.
In this embodiment, an LED element is mounted as a semiconductor device, and a package constituting a light emitting device is molded by applying the lead frame of the present invention. FIG. 1 shows a molding of the lead frame 1 of the embodiment of the present invention. An upper surface and a lower surface in a state where the package 2 is integrally molded by being installed in a mold are shown. In the figure, reference numeral 21 denotes a gate portion disposed on the lower surface of the package 2.

The lead frame 1 is made of, for example, a conductive metal strip such as a copper alloy, and is stamped and punched into a predetermined shape by pressing, and the surface is plated with silver, a silver-palladium alloy, a gold-palladium alloy, or the like. The formed one can be used.
The molding material of the package 2 is preferably a silicone resin having excellent reflection characteristics, UV resistance characteristics, and heat resistance, but a thermosetting resin other than a silicone resin such as an epoxy resin, or a thermoplastic such as PPA or PA9T. The package 2 may be molded using a resin.

  FIG. 2 shows an upper surface and a lower surface of the lead frame 1, respectively. As shown in the drawing, the lead frame 1 is a die pad in which the semiconductor element 3 is mounted integrally with an outer frame lead 11 surrounding the four sides. 12, terminal leads 13 and 13 constituting a pair of electrodes, and a pair of suspension leads 14 and 14 are provided.

  More specifically, each of the suspension leads 14 and 14 is provided with a width that substantially joins the entire length of the opposing side wall of the package 2, and three suspension leads 14 and 14 are spaced apart at equal intervals in the width direction. These vent grooves 14a are formed at the same depth.

  As shown in FIG. 3, the vent groove 14 a forms a band-like surface on the suspension lead 14 with an appropriate depth in the thickness direction over the length from the tip of the suspension lead 14 to the outer frame lead 11 at the root portion. The bottom surface of the suspension lead 14 is a flat surface.

  Further, as shown in FIG. 5, the tip ends of the suspension leads 14, 14 are provided with a tapered portion 14 b that is inclined from the top surface tip side of the suspension lead 14 to the bottom surface base side, and when the package 2 is molded, The tapered portion 14 b is inserted into the side wall of the package 2 to support the package 2.

The vent groove 14a is a portion for sending air in the cavity to the outside of the molding die when the lead frame 1 is placed in the molding die and the package 2 is molded. For example, it can be provided in an appropriate cross-sectional shape such as a rectangular groove cross section or a V-shaped notch groove cross section. As will be described later, a plurality of the terminals may be arranged at positions corresponding to the welds of the filling terminal portion.
Further, as shown in the drawing, in addition to providing the same number of the plurality of vent grooves 14 a of each suspension lead 14, one suspension groove 14 a is provided in each suspension lead 14, or the number of installation is different for each suspension lead 14. One or a plurality of vent grooves 14a may be provided. One or a plurality of vent grooves 14 a may be provided only on the surface of one of the plurality of suspension leads 14. The width and cross-sectional shape of the vent groove 14a formed in the suspension lead 14 are appropriately set according to molding conditions and the like so that the air in the cavity can be efficiently sent to the outside of the molding die.
Further, when the package 2 is molded, a roughing process is performed to increase the frictional resistance, such as providing concave or convex streaks on the surface of the vent groove 14 so that the resin does not easily adhere to the molding die side. It is preferable. In addition, it is preferable that the vent groove 14 is provided narrower than wide because the resin is peeled off from the vent groove 14 when the resin flows into the vent groove 14 and becomes clogged, and is difficult to adhere to the molding die.
Furthermore, by securing a large width of the suspension lead 14 so that the suspension lead 14 is widely joined to the side wall of the package 2, and providing an appropriate number of vent grooves 14a with an appropriate width and depth in the suspension lead 14, When the package 2 is molded, air can be discharged from the entire inside of the cavity in a well-balanced manner to enhance the vent effect.

In order to mold the package 2 using the lead frame 1 of this embodiment formed as described above, a molding die 3 shown in FIGS. 4 and 5 can be used.
Here, the molding die 3 includes an upper die 31 and a lower die 32, and the lead frame 1 installed between the upper and lower dies 31, 32 has its terminal leads 13 as shown in FIG. , 13 and the suspension leads 14 and 14 are configured to be supported in the cavity 33 by being sandwiched and pressed by the ends of the upper and lower molds 31 and 32.
Further, as shown in FIG. 6, the molding die 3 is arranged such that the position of the gate 34 for flowing the resin into the cavity 33 is such that the suspension lead 14 becomes the resin-filled end portion.

When the lead frame 1 is installed in the molding die 3 and the resin flows into the cavity 33 from the gate 34, the air in the cavity 33 is suspended by the inflow of the resin as shown in FIG. 14 and 14 are sent to the outside of the molding die 3 through the vent grooves 14a.
In this case, since the gate 34 of the molding die 3 is arranged so that the suspension lead 14 serves as the resin filling end portion, an air reservoir that is likely to be generated at the filling terminal portion in the cavity 33 is generated in the suspension lead 14. The package 2 that is efficiently discharged to the outside of the molding die 3 through the vent groove 14a and does not have insufficient resin filling can be molded.
Even if the resin flows into and clogs the vent groove 14a at the time of molding and the venting effect is lost, the resin does not adhere to the molding die 3. Therefore, when the package 2 of the next stage is molded, the resin does not enter the vent groove 14a. Since the molding is performed on a new lead frame 1 that is not attached, the package 2 can be continuously molded by sequentially installing the lead frame 1 on the molding die 3.

In the package 2 formed integrally with the lead frame 1, the LED elements 4 are mounted on the die pad 12 in the package 2, and then the terminal leads 13 and 13 are cut and the suspension leads 14 and 14 connected to the side walls of the package 2 are provided. They can be separated and handled as individual pieces as shown in FIG.
Also, the step of mounting the LED element 4 while the package 2 is supported on the lead frame 1, the step of connecting the terminal leads 12, 12 of the lead frame 1 and the electrodes of the LED element 4 with wires, the LED element 4 The terminal leads 12 and 12 connected by wires may be processed into a light emitting device through each step of covering with a sealing material, and then the processed package 2 may be removed from the lead frame 1.
Since the tapered portion 14b provided at the tip of the suspension lead 14 is connected to the peripheral portion of the package 2, the package 2 is stably supported in the lead frame 1 via the suspension lead 14 to process the package 2. The tip of the suspension lead 14 provided with the tapered portion 14b can be easily removed when the suspension lead 14 is separated from the package 2, and the portion connected to the package 2 No debris is produced.

  FIG. 8 shows a state in which the lead frame 1 according to another embodiment of the present invention is installed in the molding die 3 and the package 2 is integrally molded. The lead frame 1 of this embodiment is shown in FIG. As shown in FIG. 4, the plurality of vent grooves 14a provided in the suspension leads 14 and 14 are each formed in a V-shaped cross-sectional shape and narrower than the above-described form.

  FIG. 9 shows a state in which the lead frame 1 according to still another embodiment of the present invention is installed in the molding die 3 and the package 2 is integrally molded. Three vent grooves 14 a are provided at equal intervals on the surface of the suspension lead 14, and six vent grooves 14 a are provided on the surface of the other suspension lead 14. It is provided so that the resin 33 is uniformly filled into the cavity 33 of the molding die 3 by forming the three vent grooves 14a far from the resin filling terminal portion at a small distance. .

10 and 11 show other forms of the lead frame 1, and FIG. 10 shows a tapered portion inclined from a substantially middle portion of the tip end portion of the suspension leads 14 and 14 toward the bottom surface of the suspension lead 14. In FIG. 11, the tapered portion 14b is formed with two inclined surfaces having different angles.
Any of these illustrated taper portions 14b stably supports the package 2 in the lead frame 1 via the suspension leads 14 and 14 and separates the suspension leads 14 and 14 from the package 2. Can easily remove the tips of the suspension leads 14, 14.

  Note that the illustrated lead frame 1, package 2, and molding die 3 show an example of an embodiment of the present invention, and the present invention is not limited to this, and can be configured in other appropriate forms. It is.

DESCRIPTION OF SYMBOLS 1 Lead frame, 11 Outer frame lead, 12 Die pad, 13 Terminal lead, 14 Hanging lead, 14a Vent groove, 14b Tapered part, 2 Package, 3 Molding die, 31 Upper die, 32 Lower die, 4 LED element

Claims (8)

A lead frame having a die pad on which a semiconductor element is mounted and a terminal lead constituting an electrode, and a package in which the die pad, the terminal lead, and the resin molded body are integrated by being resin-molded by being placed in a molding die In the lead frame for forming
A plurality of suspension leads connected to and supported by the periphery of the resin molded body are provided, and a vent groove is formed on the surface of at least one of the plurality of suspension leads. Lead frame.   The lead frame according to claim 1, wherein rough processing is performed on the surface of the vent groove to increase frictional resistance.   The lead frame according to claim 1 or 2, wherein a tapered portion is provided at a tip portion of the suspension lead so as to be inclined from the top surface side of the lead to the bottom surface side.   A molding die for integrally forming a resin molding on the lead frame according to any one of claims 1 to 3, wherein the position of the gate for injecting the resin into the cavity is filled with the suspension lead A molding die for a package, which is arranged so as to be an end portion.   A molding die for integrally forming a resin molding on the lead frame according to any one of claims 1 to 3, wherein an upper die and a lower die constituting the molding die are the upper and lower dies. A molding die for a package, characterized in that it is provided so as to be sandwiched and pressed between the terminal lead of the lead frame and the edge of the suspension lead placed between the die.   A semiconductor element is mounted on the lead frame according to any one of claims 1 to 3, and an electrical terminal of the semiconductor element and a terminal lead of the lead frame are connected, and the semiconductor element is covered with a resin. A semiconductor device.   A package formed using the lead frame according to claim 1. A light emitting element is mounted on the package according to claim 7, the electrode portion of the light emitting element is connected to a terminal lead, and the light emitting element mounted in the package is covered with a sealing material. A light emitting device characterized by the above.

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