JP5923293B2 - Mold - Google Patents

Description

  The present invention relates to a semiconductor device in which a semiconductor chip is mounted and resin-sealed, and a mold used for manufacturing the semiconductor device.

  2. Description of the Related Art Conventionally, in order to manufacture a semiconductor device, a technique for performing resin sealing (transfer molding) by clamping a lead frame with a mold die in which a cavity (concave portion) is formed is known. Air is present inside the cavity before resin sealing, but the cavity is gradually filled with resin by resin being pumped during resin sealing.

  However, since the speed of the resin flowing inside the cavity varies depending on the location of the cavity, even if the resin is completely filled inside the cavity, air remains in a part thereof. In order to discharge such air from the inside of the cavity, in the conventional mold, an air vent hole (air vent) is provided outside the cavity (outer wall opposite to the gate), and the air is discharged from this hole. Was adopted.

  Patent Document 1 discloses a mold used for manufacturing an LED package. The mold is configured to clamp the lead frame in a region (projection) surrounded by a cavity formed in an annular shape in plan view.

JP 2009-206370 A

  However, when a cavity pin (projection) is arranged at the center of the cavity and the lead frame is clamped with this cavity pin and resin-sealed, the air in the cavity becomes the center of the cavity, that is, the cavity pin (projection). ) To stick to the side. For this reason, even if an air vent hole is provided outside the cavity as in the prior art, it may be difficult to remove the air clinging to the side surface of the cavity (projection). As a result, when voids are generated in the resin package, there is a possibility of adversely affecting the performance such as strength and moisture resistance of the semiconductor device.

  Therefore, the present invention provides a mold for manufacturing a high-quality semiconductor device and a high-quality semiconductor device.

A mold according to one aspect of the present invention is a mold used for manufacturing a semiconductor device by sealing a workpiece with a resin, the one mold for pressing the workpiece from one side, has a second mold to press the workpiece from the other side, the said at least one other hand the mold and the second mold cavity pin to press the workpiece, and are configured to surround the cavity pin A cavity is provided, and a tip of the cavity pin includes a pressing part that holds the workpiece, a recess that is formed inside the pressing part and traps air discharged from the cavity during resin sealing, and the resin anda passage for the air moves from the cavity to the recess during sealing, the passage is divided by the cavity pin et Said and flow of the resin is placed in a position to confluence, are composed of the resin moves the said air into said recess so as not to move into the recess.

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

  According to the present invention, it is possible to provide a mold for manufacturing a high-quality semiconductor device and a high-quality semiconductor device.

It is a schematic sectional drawing of the metal mold | die in a present Example. It is explanatory drawing of resin sealing using the metal mold | die in a present Example. It is a block diagram of the front-end | tip of the cavity pin in a present Example. It is a modification of the combination of the cavity pin and the lead frame in the present embodiment. It is a modification of the cavity pin in a present Example. It is a top view which shows the modification of the metal mold | die in a present Example.

  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.

  With reference to FIG. 1 thru | or FIG. 3, the metal mold | die (mold metal mold | die) used in order to manufacture the semiconductor device and its semiconductor device in a present Example is demonstrated. FIG. 1 is a schematic cross-sectional view of a mold in the present embodiment, showing a state in which a lead frame (semiconductor device) is clamped using an upper mold and a lower mold. FIG. 2 is an explanatory diagram of resin sealing using a mold, and shows an enlarged region surrounded by a dotted line 150 in FIG. 3A and 3B are configuration diagrams of the tip of the cavity pin in the present embodiment, FIG. 3A shows a side view of the tip, and FIG. 3B shows a plan view of the tip.

  In FIG. 1, a lead frame 10 (work) is configured 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, for example. The 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. In FIG. 1, the same configuration as that on the right side is arranged on the left side across the alternate long and short dash line, so that two lead frames 10 are resin-sealed by one molding. Note that FIG. 1 shows only a region constituting one semiconductor package after separation.

  A plurality of semiconductor chips 80 are mounted on the lead frame 10. The semiconductor chip 80 is electrically connected and fixed onto the lead frame 10 using solder or the like with the surface opposite to the surface on which the circuit is formed facing the lead frame 10 side. In the semiconductor chip 80, the circuit of the semiconductor chip 80 and a predetermined region on the lead frame 10 are electrically connected by wire bonding using a wire 82 made of gold or the like. However, the present embodiment is not limited to this, and the semiconductor chip 80 can be mounted on the lead frame 10 by flip chip using bumps. In this case, the wire 82 is unnecessary. Further, as a workpiece to be molded, a substrate such as a ceramic substrate or a resin substrate, a semiconductor wafer, or the like may be used instead of the lead frame 10. In addition, it is not always necessary to seal the semiconductor chip, and a structure (resin molded product) in which a resin structure such as a stiffener that reinforces a reflector that reflects light in a semiconductor package or a structure that is held by a heat sink is formed on a substrate or the like. Can also be adopted.

  By performing resin sealing (resin molding) on the lead frame 10 on which the semiconductor chip 80 is mounted using the mold shown in FIG. 1, the resin molded product obtained thereby is diced into individual pieces, A semiconductor package (semiconductor device) as a final product is completed. The semiconductor device of this embodiment is used as a semiconductor sensor, for example. However, the present embodiment is not limited to this, and can also be applied to semiconductor devices used for other uses such as LEDs.

  In the present embodiment, the mold is configured to include an upper mold 50 (one mold) and a lower mold 60 (the other mold). The upper mold 50 includes an upper mold insert 51, and cavity pins 52 (projections) are inserted into the upper mold insert 51. Although only one cavity pin 52 is shown in FIG. 1, a plurality of cavity pins 52 corresponding to the number of semiconductor packages are actually inserted into the upper mold insert 51. The cavity pin 52 is made of, for example, iron or stainless steel material, but is not limited thereto.

  A cavity 57 is formed in the upper mold insert 51 so as to surround each cavity pin 52. The cavity 57 is filled with resin when the lead frame 10 is resin-sealed by transfer molding. This resin seals the semiconductor chip 80 and constitutes a package in the semiconductor device after separation. In addition, the upper die 51 is formed with a through gate 58 that allows communication between adjacent cavities 57. However, an air vent may be provided instead of the through gate 58. Further, with the configuration described later, air venting is possible without providing air discharge means to the outer periphery of the package in plan view, and generation of voids can be prevented.

  Further, the upper die insert 51 is formed with a cull 55a, a runner 55b, and a gate 56, and these are provided in communication with each other so as to inject resin into the cavity 57. The upper mold 50 presses the lead frame 10 from the upper surface side (one surface side) so that the semiconductor chip mounting region and the cavity 57 overlap when the resin is sealed.

  The lower mold 60 includes a lower mold insert 61. In the lower mold insert 61, a cavity 67 is formed at a position corresponding to the cavity 57 of the upper mold insert 51, that is, a position symmetrical to the cavity 57 with the lead frame 10 interposed therebetween. Further, a protrusion 62 is formed at the center of the cavity 67 at a position corresponding to the cavity pin 52 of the upper mold insert 51, that is, at a position symmetrical to the cavity pin 52 with the lead frame 10 interposed therebetween. Further, the lower mold insert 61 is formed with a through gate 68 that allows adjacent cavities 67 to communicate with each other. The through gate 68 is provided at a position corresponding to the through gate 58 of the upper mold insert 51, that is, at a position symmetrical to the through gate 58 with respect to the lead frame 10. The lower mold 60 presses the lead frame 10 from the lower surface side (the other surface side) during resin sealing.

  As described above, the mold according to the present embodiment is mainly composed of the upper mold 50 and the lower mold 60. At the time of resin sealing (at the time of resin molding), the lead frame 10 is clamped (sandwiched) by the upper mold 50 and the lower mold 60, and the inside of the cavities 57 and 67 is filled with resin for semiconductor packages. .

  In FIG. 1, reference numeral 70 denotes a resin tablet obtained by molding a thermosetting resin or the like into a tablet (column). At the time of resin sealing, as shown in FIG. 1, the pot 63 of the lower mold 60 is preheated, and the resin tablet 70 is put therein and melted. Then, the plunger 64 configured to be slidable up and down along the pot 63 is moved up by a transfer mechanism (not shown), and the molten resin 71 is pumped. As the resin 71 is pumped by the plunger 64, the melted resin 71 passes through the cull 55a, the runner 55b, and the gate 56 in FIG. 1 as shown in FIG. Supplied to. When performing a matrix type molding in which a plurality of packages are connected through through gates 58 and 68, the cavities 57 and 67 communicate with each other through the through gates 58 and 68. Sequentially supplied from cavities 57 and 67 near gate 56 toward cavities 57 and 67 far from (distant from) gate 56. In this way, the resin tablet 70 is melted to become the resin 71 and is injected into the space (cavities 57 and 67) formed by the upper mold 50 and the lower mold 60.

  As shown in FIGS. 1 and 2A, air exists in the cavities 57 and 67 before resin sealing. Since the resin 71 is pumped by the plunger 64 and the inside of the cavities 57 and 67 is gradually filled with the resin 71, it is necessary to discharge air existing inside the cavities 57 and 67 from the cavities 57 and 67. For this reason, by providing an air vent outside the cavities 57 and 67 (a part of the outer wall), the air is discharged from the air vent as the resin 71 is filled inside the cavities 57 and 67.

  However, in this embodiment, the resin sealing is performed in a state where the lead frame 10 is clamped using the cavity pin 52 (pressing portion 91) and the protruding portion 62 (pressing portion 95) at the center of the cavities 57 and 67. In this case, as shown in FIG. 2B, when the flow of the resin 71 divided by the columnar portions of the cavity pins 52 and the protrusions 62 merges behind these columnar portions (the right side in the figure). In addition, air 57a and 67a remain in the vicinity of the columnar portion. Specifically, the air 57 a and 67 a remain so as to cling to the central portions of the cavities 57 and 67, that is, the side surfaces of the cavity pin 52 and the protrusion 62. For this reason, even if air vent holes are provided outside the cavities 57 and 67 as in the prior art, the air 57a and 67a clinging to the side surfaces of the cavity pin 52 and the protrusion 62 cannot be effectively removed. .

  Therefore, in this embodiment, a space for confining air discharged from the cavity 57 during resin sealing is formed between the tip of the cavity pin 52 and the lead frame 10. Specifically, as shown in FIGS. 3A and 3B, the tip of the cavity pin 52 includes a pressing portion 91, a concave portion 92 (digging portion), and a passage portion 93. . The holding portion 91 is a portion that holds the lead frame 10 (from the upper surface side). The recess 92 is a region that is formed inside the pressing portion 91 and traps the air 57a. The passage portion 93 serves as a passage for the air 57a to move from the cavity 57 to the recess 92 (in the direction of the arrow in FIG. 3B) during resin sealing. The passage portion 93 is provided on the opposite side of the cavity pin 52 from the gate 56 (on the right side in FIG. 3B). This is because the air in the cavity 57 is likely to be generated in a region where the resin merges. Similarly, in the present embodiment, a space (concave portion 96) for confining the air 67a is formed between the tip of the protrusion 62 and the lead frame 10.

  As described above, in this embodiment, the space for confining the air 57a and 67a in the cavities 57 and 67 is formed in both the cavity pin 52 and the tip of the protrusion 62 when the resin is sealed. For this reason, the air 57a and 67a clinging to the side surface of the cavity pin 52 and the protrusion 62 can be effectively removed. As a result, it becomes possible to manufacture a high-quality resin package by reducing voids generated in the resin package.

  By adopting such a configuration, as shown in FIG. 2C, unnecessary air 57a and 67a in the cavities 57 and 67 are removed, and the space between the upper mold 50 and the lower mold 60 ( The cavities 57, 67) are satisfactorily filled with the resin 71. Further, in order to reduce such voids, it is conceivable to discharge the air in the cavities 57 and 67 and fill the resin with reduced pressure molding or to increase the resin pressure. Compared with the method of changing the shape of the mold, an expensive apparatus configuration is required. On the other hand, according to the configuration of this embodiment, it is possible to manufacture a high-quality resin package with an inexpensive device configuration by reducing voids. 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.

  After filling with the resin 71, after waiting for a predetermined time to cure the resin 71, the upper mold 50 and the lower mold 60 are opened. Then, it is separated into a plurality of resin packages (semiconductor devices) by a dicing process. With such a configuration, it is possible to provide a high-quality semiconductor device by reducing voids in the resin package.

  Next, a modification of the present embodiment will be described with reference to FIGS. 4A to 4C are modified examples of the combination of the cavity pin and the lead frame in the present embodiment. 5A and 5B are modifications of the cavity pin in the present embodiment. 6A and 6B are plan views showing modifications of the mold in this embodiment.

  In the modification of FIG. 4A, the tip of the cavity pin 52a has the same planar shape as the conventional one. That is, the entire tip constitutes a pressing portion that holds the lead frame. On the other hand, the lead frame 10a is formed with a recess 11 (digging portion) for trapping air in an inner region of the region pressed by the cavity pin 52a. Further, the lead frame 10a is formed with a passage portion 12 for air to move from the cavity to the recess 11 during resin sealing. The concave portion 11 and the passage portion 12 have the same shapes as the concave portion 92 and the passage portion 93 of the cavity pin 52 described with reference to FIG.

  In the modification of FIG. 4B, the lead frame 10b has a recess 11 similar to that of FIG. On the other hand, a passage portion 93 is formed at the tip of the cavity pin 52b for air to move from the cavity to the recess 11 during resin sealing. The passage portion 93 has the same configuration as that described with reference to FIG.

  In the modification of FIG. 4 (c), a concave portion 92 is formed at the tip of the cavity pin 52c, which is formed inside the pressing portion and traps air. The recess 92 has the same configuration as described with reference to FIG. On the other hand, the lead frame 10c is formed with a passage portion 12a for air to move from the cavity to the recess 92 during resin sealing.

  Thus, even when each configuration of the combination of the cavity pin and the lead frame shown in FIGS. 4A to 4C is employed, the effect of the present embodiment can be similarly obtained.

  In the modification of FIG. 5A, the cavity pin 52d is provided with a hole 94 for extracting air trapped in the recess 92. One end of the hole 94 is connected to the recess 92, and the other end is connected to air suction means (not shown). By providing the hole 94, air trapped in the recess 92 does not accumulate, so that an air volume larger than the volume of the recess 92 can be sucked.

  In the modification of FIG. 5B, the cavity pin 52e has a recess 92a and a passage portion 93a. The depth (height) of the concave portion 92a and the passage portion 93a is deeper (higher) than the concave portion 92 and the passage portion 93, respectively, and is larger than the diameter of the filler contained in the resin 71, so that the flow is blocked by the filler. It is necessary to make the depth unstoppable. Further, preferably, the width of the passage portion 93 a is configured wider than that of the passage portion 93. According to the configuration of this modification, a space for confining air contained in the resin at the time of resin sealing is formed, and a part of the resin 71 is confined inside the recess 92a through the passage portion 93a. It will also have a function.

  In the mold according to the present embodiment, the cavity pin 52 is provided as a protrusion in the upper mold 50, and the protrusion 62 formed integrally with the lower mold insert 61 is provided as a protrusion in the lower mold 60. However, the present embodiment is not limited to this. A protrusion formed integrally with the upper mold insert 51 may be provided as a protrusion in the upper mold 50, and a cavity pin may be provided as a protrusion in the lower mold 60. Moreover, both protrusion parts can also be used as cavity pins. That is, a cavity pin may be employed for at least one of the protrusions of the upper mold 50 and the lower mold 60. Further, as both protrusions, protrusions formed integrally with the respective inserts can be employed.

  In the mold of this embodiment, spaces (concave portions 92 and 64) for confining air are formed in the protrusions (cavity pins 52 and protrusions 62) of both the upper mold 50 and the lower mold 60. However, the present invention is not limited to this. Such a space may be formed in at least one protrusion of the upper molds 50 and 60. Moreover, you may comprise so that such protrusion part itself may be provided in at least one of the upper metal mold | die 50,60. The configuration of the molding die in the present embodiment is appropriately changed depending on whether the semiconductor chip is formed on both sides of the lead frame or on one of the sides. In the present embodiment, the tip of the protrusion is circular when viewed from the plane direction shown in FIG. 3B, but is not limited to this, and may be other shapes such as a rectangular shape.

  In addition, in the modification of FIG. 6A, a package such as an LED reflector can be collectively formed by providing the map type cavity 57a with circular projections 59a in a plan view in a matrix. . In such a case, air can be discharged into the recess 98a by providing the passage portion 97b on the opposite side of the protrusion 56a to the gate 56. That is, since the resin merges in the vicinity of the wall surface of the projection 59a on the line connecting the gate 56 and the air vent 53, the air can be discharged at the position where the resin merges.

  In the modification of FIG. 6 (b), the map type cavity 57b is provided with projections 59b having a rectangular shape in plan view in a matrix, thereby forming, for example, a package that is molded as a stiffener for holding a heat sink, for example. can do. In such a case, even when the gap between the projections 59b becomes narrow (narrow), the gaps near the wall surface of the projection 59b on the line connecting the gate 56 and the air vent 53 are joined. For this reason, air can be smoothly discharged into the recess 98b by providing the passage portion 97b on the side surface facing the gate 56. That is, the molding position of the passage portion 97b is not limited to the side opposite to the gate 56, but the air is smoothly discharged by being arranged at a resin joining position that is confirmed by a molding test or a flow analysis as a position where the resin joins. can do.

  In the present embodiment, a space for confining air in the cavity at the time of resin sealing is formed at the tip of at least one protrusion of one mold and the other mold. For this reason, the air clinging to the side surface of the protrusion can be effectively removed, and the generation of voids in the semiconductor package can be suppressed. For this reason, according to this embodiment, it is possible to provide a mold for manufacturing a high-quality semiconductor device and a high-quality semiconductor device.

  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.

10 Lead frame 50 Upper mold 52 Cavity pin 57, 67 Cavity 58, 68 Through gate 60 Lower mold 63 Pod 64 Plunger 70 Resin tablet 71 Resin 80 Semiconductor chip 82 Wire 91 Holding part 92 Recess 93 Passage part

Claims (3)

A mold used for manufacturing a semiconductor device by sealing a workpiece with a resin,
One mold for holding the workpiece from one side;
The other mold for pressing the workpiece from the other side,
At least one of the one mold and the other mold is provided with a cavity pin that holds the workpiece, and a cavity configured to surround the cavity pin ,
The tip of the cavity pin is
A holding part for holding the workpiece;
A recess that is formed inside the pressing portion and traps air discharged from the cavity during resin sealing;
A passage for allowing the air to move from the cavity to the recess during the resin sealing ,
The passage portion is arranged at a position where the flow of the resin divided by the cavity pins merges, and is configured to move the air to the recess and not move the resin to the recess . A mold mold characterized by that. The workpiece is a lead frame;
The semiconductor device is a semiconductor sensor,
The mold according to claim 1, wherein the passage portion discharges air remaining on a side surface of the cavity pin in the cavity to the concave portion . The mold according to claim 1 or 2 , wherein the cavity pin has a hole for extracting the air confined in the recess.