JP2013512807A - Sealing material forming apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a sealing material on a substrate such as a lead frame in which a through-hole exists while being able to mold a sealing material with a reliable thickness dimension even though it is an overmold method. To provide a suitable sealing material forming apparatus.
In the present specification, a sealing material can be molded with a reliable thickness dimension even though it is an overmold method, and sealing is performed on a substrate such as a lead frame in which a through hole exists. Disclosed is a sealing material forming apparatus suitable for forming a material. The disclosed sealing material molding apparatus includes a fixed mold on which a substrate is mounted, a movable mold disposed to face the fixed mold, and an insert cavity positioned between the fixed mold and the movable mold. A resin loading space provided between the block and the insert cavity block and the movable mold, and the insert cavity block has a molding cavity facing the substrate, and a resin movement path extending from the resin loading space to the molding cavity. It is formed.
[Selection] Figure 1

Description

 The present invention relates to an encapsulant molding apparatus and method, and more particularly to an encapsulant molding apparatus and method suitable for molding an encapsulant for a light emitting diode package by an overmold method.

 In the manufacture of a package product incorporating a semiconductor chip such as a light-emitting diode chip, a technique of forming a sealing material for sealing the chip with a resin is used. Depending on the technical level and recent product characteristics and market needs, semiconductor packages such as light emitting diode packages tend to be lighter, thinner and shorter. As an effort to save such a trend and raw materials, research into a sealing material molding technique that attempts to minimize the amount of resin consumption for molding a sealing material is actively progressing.

 As conventional sealing material molding techniques, there are many known transfer molding or injection molding and overmold molding (or compression molding).

 In the case of transfer molding, in order to fill the resin before curing as a raw material into the cavity where the molding is performed, the resin is temporarily supplied to the pot provided in the mold, and the upper mold and the lower mold are closed. In this state, an external force is applied to the pot so that the resin enters the cavity through the runner and the gate sequentially. The resin that has passed through the gate is completely filled in the cavity, and then cured when a predetermined time elapses. The sealing material or the product containing the sealing material is separated from the mold. At this time, the resin remaining in the pot, the runner, and the gate is discarded after the separation work with the product.

 As described above, the conventional transfer molding (or injection molding) has many paths through which the resin is transferred. Therefore, a large amount of resin flow is required, and the pot, runner, The volume of the gate is large, and the pot, runner, and the resin in the gate are discarded, so that there is a disadvantage that the amount of resin consumption becomes excessive. Therefore, transfer molding has a problem that it is extremely inferior in economic efficiency due to excessive resin consumption, despite the advantages of good molding accuracy and high molding dimension stability.

 On the other hand, in contrast to the transfer molding method, overmold molding reduces the amount of resin consumption by supplying resin directly to the cavity and molding it by applying pressure without a pot, runner, or gate. There was an economic advantage of being able to. However, in the conventional overmolding, the volume of the cavity shrinks or changes in the molding thickness direction during pressurization, so that a difference in molding thickness may occur depending on the degree of resin supply. Further, the conventional overmolding has an advantage in forming a sealing material for a large number of elements at once, but there is a problem that it is difficult to cope with a specific product. In particular, the conventional overmolding technology may cause the resin to flow out of the through holes when molding a sealing material on a semiconductor chip on a lead frame substrate having a large number of through holes. There were inconveniences and annoyances such as requiring pre-protection measures to close the through hole with tape.

 In the case of a surface mount type light emitting diode package that occupies the majority of light emitting diode package products, a reflector surrounding the periphery of the light emitting diode chip is required to increase the light efficiency. The reflector is a molded product in which PPA is injection-molded and integrated on a lead frame substrate formed by patterning a metal, and includes an opening for accommodating a semiconductor chip. When overmolding is used for such an application, a sealing material or a lens must be molded so as to cover the opening. Therefore, when the resin is applied over the entire cavity of the lower mold, the outer shell of the reflector is included. The sealing material is molded up to an unnecessary portion of the lead frame. This increases the amount of consumed resin as the distance or pitch between elements or packages increases, and there is also a base that causes other additional problems in the processes after the molding process. In addition, when thinly molded to reduce the amount of resin that is discarded, the adhesion between the reflector and the sealing material is inferior, so the sealing material is removed during the steps after molding, causing other problems. Sometimes it happens.

 The object of the present invention is to form an encapsulant on a substrate such as a lead frame in which a through hole is present, while being able to form an encapsulant with a reliable thickness while being an overmold system. An object of the present invention is to provide a sealing material forming apparatus suitable for the purpose.

 Another object of the present invention is to use an overmolding molding apparatus to reliably provide a sealing material on a substrate, particularly a substrate including a hole in which a through hole is present, without additional precautions. It is providing the sealing material shaping | molding method shape | molded by the dimension.

 The sealing material molding apparatus according to one aspect of the present invention includes a fixed mold on which a substrate is mounted, a movable mold disposed to face the fixed mold, and the fixed mold and the movable mold. An insert cavity block positioned therebetween, and a resin loading space provided between the insert cavity block and the movable mold, the insert cavity block having a molding cavity facing the substrate, and the resin A resin movement path that extends from the loading space to the molding cavity is formed. Here, the resin movement path is formed in the insert cavity block so as to connect the resin loading space and the molding cavity when the substrate, the insert cavity block, and the resin loading space are in continuous contact with each other. It has a resin inlet.

 According to one embodiment, the movable mold is raised or lowered until it comes into contact with the insert cavity block, and then the cavity holding block is stopped. After the cavity holding block is stopped, the movable mold is further raised or lowered, And a cavity pressurizing block that pressurizes the resin toward the insert cavity block, and the release film is covered so as to cover the upper part of the cavity holding block and the upper part of the cavity pressurizing block.

 According to another aspect of the present invention, a substrate is mounted on a fixed mold, one or more molding cavities are formed in contact with the substrate using an insert cavity block, and a resin in a resin loading space is formed using a movable mold. There is provided a sealing material molding method in which a molding material is pressurized in the molding cavity and a sealing material is molded in the molding cavity.

 The present invention has the following effects.

 First, since molding is performed through an immovable cavity space formed while the substrate and the insert cavity block are in close contact with each other, it is possible to stabilize the dimensions of the sealing material regardless of the degree of resin supply.

 Secondly, by shortening the distance between the position where the resin is supplied and pressed and the molding cavity that is the sealing material forming space, the resin movement path such as unnecessary pots and runners is minimized and discarded. The amount of consumption can be minimized.

 Thirdly, since several elements arranged in the lead frame can be individually sealed by the insert cavity block, even if there is a through hole in the molding area of the lead frame, no additional blocking measures are taken. Furthermore, resin leakage can be prevented.

 Fourth, when determining the shape of the encapsulant, the insert cavity block, which is an element that directly affects the quality of the encapsulant, does not have to be assembled in the mold in an inserted form, so that high temperature heavy fixation The cavity state can be easily confirmed and maintained without separately separating the mold or the movable mold.

 Fifth, the location where molding is not possible or unnecessary can be easily eliminated by selectively blocking the resin inlet of the insert cavity block, regardless of the amount of resin supplied. The sealing material molded with the same dimensions is obtained.

 Sixth, in the case of a structure in which the substrate is arranged in the movable mold, a cavity pressurizing block for resin pressurization is arranged on the upper part, so that a release film is provided in order to provide a predetermined space for containing the resin Need not be adsorbed by a vacuum method, and further, there is no need for a separate vacuum apparatus and apparatus for the vacuum adsorption.

It is sectional drawing which showed the sealing material shaping | molding apparatus by one Example of this invention in the 1st position. It is sectional drawing which showed the sealing material shaping | molding apparatus by one Example of this invention in the 2nd position. It is sectional drawing which showed the sealing material shaping | molding apparatus by one Example of this invention in the 3rd position. It is sectional drawing which expanded and showed a part of sealing material shaping | molding apparatus by one Example of this invention shown in FIG. It is sectional drawing which showed one application example of the sealing material shaping | molding apparatus suitable for forming a sealing material in the board | substrate which has a protrusion part in the back surface. It is sectional drawing which showed the sealing material shaping | molding apparatus by other Example of this invention.

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the embodiments of the present invention are provided in order to more fully explain the present invention to those having ordinary skill in the art, and the following embodiments are described in various other forms. The scope of the present invention is not limited to the following examples.

 1, 2, and 3 show a sealing material molding apparatus according to an embodiment of the present invention in a first position at the initial stage of molding, a second position at the middle stage of molding, and a third position at the stage of completion of molding. FIG. 4 is an enlarged cross-sectional view of the main part of FIG.

 As shown in FIGS. 1 to 3, the sealing material molding apparatus according to the present embodiment is an overmolding or compression molding molding apparatus, and includes an upper fixed mold 20, a lower movable mold 30, and a space between them. The insert cavity block 40 is provided. Although not shown in the drawings, for example, an elevating drive device such as a press pressurizing device is used for pressure molding of the resin by raising or lowering the movable mold.

 The stationary mold 20 and the movable mold 30 are disposed opposite to each other on the upper and lower parts of a lifting / lowering driving instrument such as a breath pressurizing device. The fixed mold 20 and / or the movable mold 30 may be provided with a heating device (not shown) for heating the resin to a set temperature. In this embodiment, a sealing material is formed on a substrate 10 having a lead frame 11, and the substrate 10 has a light emitting diode chip 12 mounted on the lead frame 11 and an opening for accommodating the light emitting diode chip 12. And a reflector 13 formed with a portion. The substrate 10 is cut after the sealing material is formed and separated into a plurality of SMD type light emitting diode packages, and through holes are formed in the substrate 10 due to the pattern of the lead frame 11. In the present specification, the term “substrate” means that includes all types of objects mounted on the fixed mold 20 or the movable mold 30 for molding the sealing material. Further, according to the drawing, the substrate, which is the object on which the sealing material is formed, is formed by mounting the light emitting diode chip on the lead frame, but it should be noted that the present invention should not be limited to this.

 The substrate 10 is supplied to the fixed mold 20 by a substrate supply device (not shown) provided separately, and is mounted on the fixed mold 20. As a method of mounting the substrate 10 on the fixed mold 20, a vacuum suction method or a clamp method may be used, and mounting of the substrate 10 on the fixed mold 20 by other methods is also considered. The supply of the substrate 10 by the substrate supply device is performed in a state where the fixed mold 20 and the movable mold 30 are separated by a predetermined interval by the press movable part. The substrate 10 mounted on the fixed mold 20 has a wide surface on which the sealing material is formed toward the movable mold 30.

 Further, the insert cavity block 40 is mounted on the substrate 10 mounted on the fixed mold 20. As shown in FIG. 4, the insert cavity block 40 has a plurality of molding cavities 41 on one surface, and a plurality of resin inlets (or gates 42) connected to the molding cavities 41 on the opposite surface. Is provided. The insert cavity block 40 has the substrate 10 such that the plurality of molding cavities 41 are directed toward the substrate 10, and the resin inlets 42 are directed toward the resin loading space 38 of the movable mold 30. It is attached to.

 As described above, the light emitting diode chip 12 and the reflector 13 in which the opening for receiving the light emitting diode chip 12 is formed are provided on one surface of the substrate 10, and the sealing material is the opening of the reflector 13. It is necessary to form so as to fill the part. For such a requirement, the reflector 13 is fitted into the molding cavity 41 of the insert cavity block 40. Therefore, the space that is actually filled with the resin R in the molding cavity 41 remains only in the opening of the reflector 13. In order to make the shape of the sealing material into a desired shape, the shape of the molding cavity 41 can be designed into a convex lens shape as shown in the figure or another desired shape.

 The resin existing in the resin loading space of the movable mold 30 is pressurized and flowed into the molding cavity 41 through the resin inlet 42 by the pressurization by the cavity pressurizing block 31, and then cured to open the reflector 13. A sealing material for sealing the light emitting diode chip 12 is formed on the portion. Unlike the present embodiment, when the reflector 13 is not provided on the substrate 10, the resin is filled up to the space occupied by the reflector 13 in the drawing.

 1 to 3, the movable mold 30 has a cavity pressurizing block 31 and a cavity holding block 36 disposed on the base 3. The base 3 is connected to an elevating drive device (not shown) and is configured to be driven up and down by the elevating drive device. The cavity pressurizing block 31 is fixedly disposed in a central region of the upper surface of the base 3, and the cavity holding block 36 is urged by an elastic member 37 provided on the base 3. When the base 3 is driven up, the cavity pressurizing block 31 and the cavity holding block 36 are raised together, and the cavity holding block 36 is stopped by contact with other elements (in this embodiment, the insert cavity block 40). Thereafter, with the compression of the elastic member 37, only the cavity pressurizing block 31 rises to a certain height.

 According to the present embodiment, the cavity pressurizing block 31 is always positioned lower than the outer cavity holding block 36, so that the cavity pressurizing block 31 is located above the movable mold 30 defined by the cavity pressurizing block 31 and the cavity holding block 36. A hollow space into which the molten resin is placed is formed. Further, the sealing material molding apparatus according to the present embodiment prevents the molten resin from directly contacting the movable mold 30 during pressure molding, and prevents the molten resin from leaking below the movable mold 30. A release film 50 covering the upper part of the movable mold 30 is provided. The release film 50 is adsorbed to the upper part of the movable mold 30 by a vacuum device (not shown) installed on the movable mold 30 side while being covered with the upper part of the movable mold 30.

 At this time, the release film 50 is vacuum-adsorbed through a narrow gap between the cavity pressurizing block 31 and the cavity holding block 36 of the movable mold 30, and in this way, during the pressurizing process, the outside of the resin A resin loading space 38 that can prevent leakage is formed. A certain amount of solid or liquid resin is uniformly loaded in the resin loading space 38.

 Hereinafter, the process of forming the sealing material on the substrate with the above-described sealing material forming apparatus will be further described with reference to FIG. 1, FIG. 2, and FIG.

 Referring to FIG. 1, first, the substrate 10 is mounted on the upper fixed mold 20, and then the insert cavity block 40 is mounted on the substrate 10. A resin loading space 38 is formed by adsorbing the release film 50 on the upper part of the movable mold 30 having a concave shape due to a step between the cavity pressurizing block 31 and the cavity holding block 36. In this embodiment, the insert cavity block 40 is mounted on the substrate 10 on the fixed mold 20, but it is also considered that the insert cavity block 40 is mounted on the upper part of the movable mold 30 on which the release film 50 is adsorbed. Is done. In the position shown in FIG. 1, all the parts of the movable mold 30 are separated from all the elements on the fixed mold 20 side.

 Referring to FIG. 2, when the base 3 is driven up by the elevating drive device, the cavity holding block 36 of the movable mold 30 comes into contact with the insert cavity block 40 and stops. Thereby, the resin loading space 38 is completely closed between the insert cavity block 40 and the movable mold 30. At this time, the actual contact portions are the release film 50 and the insert cavity block 40, but the release film 50 may be omitted if the resin leakage can be prevented by other means. The portion that primarily contacts the block 40 will be described as the cavity holding block 36.

 As shown in FIG. 3, when the base 3 is further driven to rise by the elevating drive device, the compression of the elastic member 37 causes the cavity pressurizing block 31 to further rise and pressurize the resin in the resin loading space 38. . The resin loading space 38 is gradually reduced by the pressurization. As shown in FIG. 4, when the damper surface 43 where the reflector 13 and the insert cavity block 40 abut is further pressurized, the resin can be prevented from transferring to the cavity region, and the sealing force can be further improved. Can do. As described above, the resin is directly pressurized while the resin loading space 38 is reduced, and the pressurized resin enters the molding cavity 41 from the resin inlet 42 provided in the insert cavity block 40. Injected.

 Further, in the process of each step, a vacuum passage, that is, an air vent, is formed in order to effectively remove bubbles (voids) contained or generated in the molding and improve moldability. The upper surface of the cavity holding block 36 forming the outline of the resin loading space 38, the upper surface of the reflector 13, and the surface where the insert cavity block 40 abuts can be selectively provided.

 The resin pressed into a liquid state is cured after a certain time. When the resin is cured, the fixed mold 20 and the movable mold 30 are separated from each other, the substrate 10 and the insert cavity block 40 are collectively unloaded using a material supply device (not shown), and collectively outside the mold. It is possible to separate or unload the insert cavity block 40 first, and then to remove the substrate after the molding of the sealing material is completed.

 FIG. 5 shows an application example in the case where the back surface of the substrate 10, that is, the surface opposite to the surface on which the sealing material is formed is not a flat surface. When there is a protrusion 19 on the back surface of the substrate 10, a relief groove 27 corresponding to the protrusion 19 is provided in the fixed mold 20 to prevent the substrate 10 from being lifted. The escape groove 27 may be generated not only by the correspondence to the protrusion 19 but also by the deviation formed by the upper surfaces of the multiple reflectors 13 and the deviation of the damper surface 43 (see FIG. 4) of the insert cavity block 40. The gap on the outer peripheral surface of the molding cavity 41 can be eliminated. A part of the substrate 10 is elastically pushed by the escape groove 27 formed in the fixed mold 20, and the above-described deviation is canceled by the spring back action, and the sealing force can be further improved.

 FIG. 6 is a cross-sectional view showing a sealing material forming apparatus according to another embodiment of the present invention. Although based on the mechanism introduced in the embodiment described above, the mounting direction of the substrate 10 is different. That is, according to the present embodiment, the movable mold 30 is arranged at the upper part to constitute the upper mold, and the fixed mold 20 is arranged at the lower part to constitute the lower mold. The substrate 10 is mounted on the lower fixed mold 20, and the insert cavity block 40 is mounted thereon. One surface of the insert cavity block 40 is provided with a molding cavity 41 opened toward the lower mold, that is, the substrate 10 attached to the fixed mold 20, and the opposite surface, that is, the surface facing the movable mold 30. Are formed with a resin loading space 38 and a resin inlet 42 connecting the resin loading space 38 to the molding cavity. A release film 50 is disposed below the movable mold 30 or above the insert cavity block 40 so as to be positioned below the resin loading space 38. The movable mold 30 is moved down primarily, the cavity holding block 36 of the movable mold 30 is brought into contact with the insert cavity block 40 through the release film 50, and the cavity pressurizing block 31 is compressed by the elastic member 37. Is further lowered to pressurize the resin in the resin loading space 38. The resin is injected from the resin loading space 38 through the resin inlet into the molding cavity with a large pressure. A liquid resin in the molding cavity is cured, dense, and a sealing material having a stable thickness is formed in the molding cavity. Even if it is not vacuum suction, since the release film 50 can be maintained as it is in the lower fixed mold 20, that is, the lower mold, a vacuum device for vacuum suction of the release film 50 can be omitted. . It is also possible to consider forming the relief groove 27 as shown in FIG.

20 fixed mold 30 movable mold 38 resin loading space 40 insert cavity block 41 molding cavity 50 release film

Claims (3)

A fixed mold on which the substrate is mounted;
A movable mold disposed to face the fixed mold;
An insert cavity block located between the stationary mold and the movable mold;
A resin loading space provided between the insert cavity block and the movable mold,
The sealing material molding apparatus, wherein the insert cavity block is formed with a molding cavity facing the substrate, and a resin movement path connected to the molding cavity from the resin loading space. The movable mold is raised or lowered until it comes into contact with the insert cavity block, and then the cavity holding block to be stopped, and after the cavity holding block is stopped, the movable mold is further raised or lowered, and the resin in the resin loading space is moved to the A release film is covered so as to cover an upper part of the cavity holding block and an upper part of the cavity pressurization block. The sealing material shaping | molding apparatus of description. Attaching the substrate to the fixed mold; and
Forming one or more molding cavities in contact with the substrate using an insert cavity block;
Pressurizing the resin in the resin loading space into the molding cavity using a movable mold; and
Molding a sealing material in the molding cavity;
The sealing material shaping | molding method characterized by including this.

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