JP5514366B2 - Sealing material molding method - Google Patents

Description

 The present invention relates to a semiconductor chip sealing material molding technique, and more particularly to a sealing material molding technique suitable for molding a sealing material of a light emitting diode package product.

 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.

 On the other hand, an expensive release film has been conventionally used for product separation after molding of a sealing material. Typical release films include fluorine components having non-adhesive properties, such as fluorine composites such as PTFE, PFA, FEP, and ETFE (trade name; Fluon (R) ETFE) manufactured by Asahi Glass Co., Ltd. There is a resin film. In the prior art, because of the use of an expensive release film, there is a disadvantage that the economy becomes worse. Besides that, solid residual resin supports the mold on the opposite side of the release film, that is, the product. This causes a problem that it is fixed to the mold or block and cannot be separated. In order to remove such surplus resin, a complicated additional work is further required. Further, when the sealing material is further compression-molded using a mold or block from which excess resin has not been removed cleanly, the molding quality of the sealing material is lowered, and many defects are caused.

 The present invention has been made in view of the above problems, and an object of the present invention is to provide an improved sealing material molding method in which it is easy to remove excess solid resin after the sealing material is molded. It is in.

 To achieve the above object, a sealing material molding method according to an aspect of the present invention includes an insert cavity block placement step of placing an insert cavity block having a resin inlet and a molding cavity on a substrate, and the insert cavity block, A resin loading space forming step for forming a resin loading space surrounded by a film on the opposite side, a bottom portion of the resin loading space is brought close to the insert cavity block, and the resin in the resin loading space is formed from the resin inlet through the molding A sealing material forming step that fills the cavity, and a film separating step that separates and removes the remaining solid resin remaining on the surface of the insert cavity block after the resin is cured, in a state of being adhered to the film.

 Preferably, in the insert cavity block arranging step, a release agent material is applied to a surface of the insert cavity block facing the resin loading space.

 Preferably, the step of disposing the insert cavity block includes mounting the substrate on a first mold and mounting the insert cavity block on the substrate.

 Preferably, in the resin loading space forming step, the resin loading space is formed by covering the second mold having a depressed space facing the first mold and forming the resin loading space. The mold includes a cavity pressure block and a cavity holding block disposed around the cavity pressure block, and the recessed space is formed by a height difference between the cavity holding block and the cavity pressure block.

 Preferably, in the sealing material forming step, the cavity holding block is moved up or down until it comes into contact with the insert cavity block, and the cavity pressing block is stopped after the movement. Is further moved up or down, and the resin in the resin loading space is injected into the molding cavity, and the film separating step causes the second mold and the insert cavity block to move away from each other, and the film is adhered to the film. The remaining solid resin is separated from the insert cavity block.

 The first mold may be an upper mold or a lower mold. When the first mold is an upper mold, the second mold is a lower mold, and vice versa. When the first mold is the lower mold, the second mold is the upper mold.

 According to the present invention, when a sealing material for sealing a semiconductor such as a light-emitting diode chip is compression-molded on a substrate, an expensive release film does not have to be used, which is excellent in economic efficiency.

 Further, the solid surplus resin can be easily removed from the insert cavity block and the sealing material, and the product production cost can be dramatically reduced.

 Further, it is possible to solve the conventional quality deterioration problem caused by the fact that the solid surplus resin and the release film are not separated from the product sealing material.

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 shows the process of isolate | separating and removing surplus solid resin with a film after sealing material shaping | molding by one Example of this invention. FIG. 6 is an actual photograph showing a film separated and removed together with the residual solid resin by the process shown in FIG. 5. It is a figure for demonstrating the sealing material shaping | molding method by the other Example of this invention. It is a figure for demonstrating the sealing material shaping | molding method by the 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. FIG. 5 is a cross-sectional view showing a state where the surplus resin is separated after the molding of the sealing material is completed.

 As shown in FIGS. 1 to 5, the sealing material molding apparatus according to the present embodiment is an overmolding or compression molding molding apparatus, and includes an upper mold 20, a lower mold 30, and an insert cavity block therebetween. 40. Although not shown in the drawings, for example, a lift driving device such as a press pressurizing device is used for pressure molding of the resin by raising or lowering the lower mold.

 The upper mold 20 and the lower mold 30 are disposed opposite to each other on the upper and lower parts of an elevating drive device such as a breath pressurizing device. The upper mold 20 and / or the lower 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 this specification, the term “substrate” means one including all types of objects mounted on the upper mold 20 or the lower mold 30 for molding a 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 upper mold 20 by a substrate supply device (not shown) provided separately, and is mounted on the upper mold 20. As a method of mounting the substrate 10 on the upper mold 20, a vacuum suction method or a clamp method may be used, and mounting of the substrate 10 on the upper mold 20 by other methods is also considered. The supply of the substrate 10 by the substrate supply apparatus is performed in a state where the upper mold 20 and the lower mold 30 are separated by a predetermined interval by the press movable part. The substrate 10 mounted on the upper mold 20 is such that a wide surface on which the sealing material is formed faces the lower mold 30.

 Further, the insert cavity block 40 is mounted on the substrate 10 mounted on the upper 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 plurality of resin inlets 42 are directed toward the resin loading space 38 of the lower 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 lower mold 30 is pressurized and flows 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, 2, 3, and 5, the lower mold 30 includes 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 positioned above the lower mold 30 defined by the cavity pressurizing block 31 and the cavity holding block 36. A recessed space is formed.

 On the other hand, the sealing material forming apparatus according to the present embodiment is a film installed in a depressed space formed by the cavity pressurizing block 31 and the cavity holding block 36, more specifically, a non-release film 50. Is provided. The film 50 defines a variable volume resin loading space 38 that can accommodate a molten resin due to the contour of the recessed space. The film 50 prevents the molten resin from coming into direct contact with the lower mold 30 and prevents the molten resin from leaking below the lower mold 30.

 The film 50 is vacuum-adsorbed through a narrow gap between the cavity pressurizing block 31 and the cavity holding block 36 of the lower mold 30, and this process prevents external leakage of the resin during the pressurizing process. A resin loading space 38 is formed. A certain amount of solid or liquid resin is uniformly loaded in the resin loading space 38.

 The film 50 is adsorbed on the upper part of the lower mold 30 by a vacuum device (not shown) installed on the lower mold 30 side while being covered on the upper part of the lower mold 30. As shown in FIG. 5, unlike the conventional release film, the film 50 is adhered to the resin in the sealing material molding process, and after the molding of the sealing material, the film 50 is strongly adhered to the remaining solid resin. . Therefore, when the film 50 is separated, excess solid resin is separated together with the film 50. The film 50 may be a general heat-resistant film that can be used in a temperature range where molding of the sealing material is performed, for example, 130 to 200 ° C., and is cheaper than a release film, such as polyethylene ( PE), polypropylene (PP), polyethylene terephthalate (PET) and the like are used. In particular, polyethylene terephthalate (PET) films are used for various applications in the general industry, electrical and electronic, packaging, graphic, display industries, and the like, and are inexpensive and easy to supply and demand.

 On the other hand, the surface of the insert cavity block 40 in contact with the resin has an interface separation characteristic with respect to the resin at least when the sealing material is molded. In order to impart the interface separation characteristic, it is preferable to apply a release agent substance 401 (see FIG. 4) to the surface of the insert cavity block 40 that contacts the resin.

 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, FIG. 3, and FIG.

 Referring to FIG. 1, first, the substrate 10 is mounted on the upper mold 20, and then the insert cavity block 40 is mounted on the substrate 10. At this time, a release agent material may be applied to the surface of at least one region of the insert cavity block 40.

 In addition, the resin loading space 38 is formed by adsorbing the heat-resistant film 50 on the upper part of the lower mold 30 having a space depressed due to the height difference between the cavity pressurizing block 31 and the cavity holding block 36. At this time, the resin loading space 38 is located on the side facing the insert cavity block 40. The film 50 should only withstand the sealing material molding temperature and have a greater adhesive force to the residual solid resin than the surface adhesive force of the insert cavity block 40 after the molding of the sealing material. As described above, a release agent material may be used to lower the surface adhesion properties of the insert cavity block 40 relative to the resin.

 The order of the process of arranging the insert cavity block 40 on the substrate 10 and the process of forming the resin loading space 38 may be changed, and these two processes may be performed simultaneously.

 In the first position shown in FIG. 1, all parts on the lower mold 30 side are separated from all elements on the upper mold 20 side.

 Referring to FIGS. 2 and 3, the liquid or gel resin loaded in the resin loading space 38 is made closer by bringing the resin loading space 38 loaded with the liquid or gel resin and the insert cavity block 40 closer to each other. The process of filling the molding cavity 41 of the insert cavity block 40 is shown. The resin is filled into the molding cavity 41 from the resin inlet 42, whereby the plurality of resin inlets 42 are configured to connect the corresponding molding cavities 41 and one resin loading space 38. It is preferable.

 As shown in FIG. 2, when the base 3 is driven up by the elevating drive device, the cavity holding block 36 of the lower mold 30 comes into contact with the insert cavity block 40 and stops. Thereby, the resin loading space 38 defined by the film 50 is completely closed between the lower mold 30 covered with the film 50 and the insert cavity block 40 facing the lower mold 30.

 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.

 As shown in FIG. 3, the resin pressurized in a liquid state is cured after a certain period of time, whereby the substrate 10 has a lens-shaped sealing material defined by the molding cavity 41 of the insert cavity block 40. It is formed. At this time, the excess solid resin to be removed remains as it is between the insert cavity block 40 and the film 50 from the resin inlet 42.

 Referring to FIG. 5, the lower mold 30 is lowered and the upper mold 20 and the lower mold 30 are separated. The substrate 10 mounted on the upper mold 20 and the insert cavity block 40 mounted on the substrate 10 are separated from the lower mold 30 and the film 50 provided on the upper surface of the lower mold 30. At this time, the remaining residual solid resin R ′ excluding the resin which is cured in the molding cavity 41 and becomes the sealing material is separated from the insert cavity block 40 together with the film 50 while being strongly adhered to the film 50. The Therefore, the residual solid resin R ′ is removed cleanly from the insert cavity block 40 and the surface of the sealing material.

 As described above, the present invention uses a strongly adhesive heat-resistant film that is strongly bonded to a solid resin, not a release film, and further has an interface separation characteristic on the surface of the insert cavity block 40 in contact with the resin. By applying a strong material such as a release agent material, the residual solid resin R ′ can be cleanly removed from the sealing material and the insert cavity block 40 together with the film 50 after molding the sealing material.

 On the other hand, the substrate 10 and the insert cavity block 40 are collectively unloaded using a material supply device (not shown) and separated to the outside of the mold, or the insert cavity block 40 is first unloaded and separated. After that, the substrate after the molding of the sealing material can be removed.

 FIG. 6 shows the film removed from the mold and the insert cavity block after the process shown in FIG. 5, and it can be seen that the residual solid resin was removed while adhering to the film. . At this time, it can be seen that a part of the residual solid resin that filled the resin inlet or gate was separated with the shape of the resin inlet or gate intact.

 7 and 8 are views for explaining a sealing material molding method using a sealing material molding apparatus according to another embodiment of the present invention.

 The sealing material molding method shown in FIG. 7 is the same as the above-described embodiment except that the mounting direction of the substrate 10 is opposite.

 Referring to FIG. 7, the movable mold 300 is disposed on the upper part to constitute the upper mold, and the fixed mold 200 is disposed on the lower part to constitute the lower mold. The substrate 10 is mounted on the lower mold, that is, the fixed mold 200, and the insert cavity block 400 is mounted thereon. One surface of the insert cavity block 400 is provided with a molding cavity 410 opened toward the lower mold, that is, the substrate 10 mounted on the fixed mold 200, and faces the opposite surface, that is, the movable mold 300. A resin loading space 38 and a resin inlet 420 that connects the resin loading space 38 to the molding cavity are formed on the surface. A film 50 is disposed below the movable mold 300 or above the insert cavity block 40 so as to be positioned below the resin loading space 380. Similar to the embodiment described above, the film 500 surrounds the resin loading space 380. The movable mold 300 is first lowered, the cavity holding block 360 of the movable mold 300 abuts the insert cavity block 400 through the film 500, and the cavity pressurizing block 310 is accompanied by compression of the elastic member 370. And further pressurizes the resin in the resin loading space 380. The resin is injected from the resin loading space 380 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 film 500 can be maintained as it is in the lower fixed mold 200, that is, the lower mold, a vacuum device for vacuum suction of the film 500 can be omitted.

 As shown in FIG. 8, after molding the sealing material, when the film 500 is separated from the insert cavity block 400, the remaining solid resin R ′ remaining on the surface of the insert cavity block 400 is adhered to the film 500 after molding. And separated from the surface of the insert cavity block 400. Similar to the embodiment described above, a release agent material can be applied to the surface of the insert cavity block 400. In FIG. 8, the upper movable mold is not shown.

10 Substrate 11 Lead frame 12 Light emitting diode chip (or semiconductor chip)
13 Reflector 20 Upper mold 30 Lower mold 31 Cavity pressure block 36 Cavity holding block 37 Elastic member 40 Insert cavity block 41 Molding cavity 42 Resin inlet 43 Dumbar surface 50 Film 401 Release agent substance R Resin R 'Surplus solid resin

Claims (4)

An insert cavity block placement step of placing an insert cavity block having a resin inlet and a molding cavity on a substrate;
A resin loading space forming step for forming a resin loading space surrounded by a film on the side facing the insert cavity block;
A sealing material molding step of bringing the bottom of the resin loading space close to the insert cavity block and filling the resin in the resin loading space from the resin inlet into the molding cavity;
After curing of the resin, it saw including a separation, and film separation step of removing in a state where the remaining residue solid resin on the surface of the insert cavity block was bonded to the film,
In the insert cavity block arranging step, a mold release material is applied to a surface of the insert cavity block facing the resin loading space . The insert cavity block arranging step includes:
2. The sealing material forming method according to claim 1, comprising: mounting the substrate on a first mold; and mounting the insert cavity block on the substrate . In the resin loading space forming step, the resin loading space is formed by covering the second mold having a depressed space facing the first mold and forming the resin loading space. has a cavity pressure block and arranged cavities holding block its periphery, said recessed space, characterized in that it is formed by the height difference between the cavity holding block and said cavity pressurization block claims Item 3. A sealing material molding method according to Item 2 . The sealing material forming step raises or lowers the cavity holding block until it abuts on the insert cavity block, and further raises the cavity pressure block while the cavity holding block is stopped after moving. Alternatively, the resin is moved downward to inject the resin in the resin loading space into the molding cavity, and the film separating step is to keep the second mold and the insert cavity block away from each other, and adhere to the film and the film. The sealing material molding method according to claim 3, wherein the residual solid resin is separated from the insert cavity block .

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