JP3677763B2 - Mold for semiconductor device manufacturing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold for manufacturing a semiconductor device used for sealing a wiring board (substrate, lead frame) or the like on which a semiconductor chip is mounted with a resin.
[0002]
[Prior art]
FIG. 10 shows a compression mold conventionally used as a mold for manufacturing a semiconductor device. As shown in FIG. 10, the conventional compression mold includes a first mold 51, a frame-shaped mold 53 that is disposed opposite to the first mold 51 and has an opening 52, and this The first mold 51 and the second mold 55 are configured by a second mold 55 including a compression mold 54 that is fitted into the opening 52 and can move up and down. The lift mechanism 56 does not operate.
[0003]
A molded product 57 to be processed is disposed between the first and second molds 51 and 55, and the wiring board of the molded product 57 is formed by the first mold 51 and the frame-shaped mold 53. Clamp the periphery of Thereafter, the compression mold 54 on which the sealing resin 58 is placed is moved relatively to the first mold 51 side by the elevating mechanism 56 to heat and melt the sealing mold 54 on the compression mold 54. The resin 58 is pressed against the molded product 57, and the resin is sealed by compression molding as shown in FIG.
[0004]
In the case of compression molding as described above, the molded product 57 is disposed between the first and second molds 51 and 55, and the molded product 57 is sandwiched between the two molds, thereby forming the molded product. A space M formed by 57 and the second mold 55 is sealed. Then, by raising the compression mold 54, which is a constituent member of the second mold 55, to the first mold 51 side, the molten sealing resin is pressurized and fluidized, and the air in the space M is made to flow. Extrude to the outer periphery.
[0005]
A narrow groove-like gap (air vent) is formed on the surface of the frame-shaped mold 53 which is a constituent member of the second mold 55, and the product 57 is placed on the second mold. Even when sandwiched between the first mold and the air vent, the air vent communicates with the outside, and the air that has moved to the outer periphery by the molten resin during the molding process is discharged from the air vent.
[0006]
[Problems to be solved by the invention]
However, in the conventional compression molding method as described above, the space sealed by the molded product 57 and the second mold 55 by the flow tip obtained by crushing and flowing the resin by the compression mold 54 that moves up and down. Since the air in M was discharged to the outside, there was a problem that the exhaust from only the air vent had high resistance, and air was trapped at the flow front end or air outside the air vent was left behind.
[0007]
In addition, due to the recent thinning of semiconductor devices, in the sealing of some semiconductor devices, when the conventional tablet-like resin is compressed and molded, the flow distance of the molten resin becomes longer during the molding process, and the inside of the cavity In some cases, it could not be filled. As a means for solving such a problem, there has been proposed a method of performing molding by supplying the granular resin to be distributed over the entire cavity surface using granular resin before molding the tablet crushed grains or tablets. Yes. However, in the conventional compression molding method, the resin starts to melt before the exhaust proceeds, and air is trapped in the molten granular resin, which may remain in the molded product and become a void.
[0008]
In order to improve such a problem, a seal for sealing is provided between the first and second molds as used in the conventional transfer mold, and the first or second facing is provided. A method of exhausting air between the first and second molds forcibly by providing an exhaust hole in a place where it cannot come into contact with the resin on the surface is conceivable.
[0009]
However, this method has the following problems. In the exhaust from the air vent, the exhaust hole takes a long time because the cross-sectional area of the exhaust hole is small and the exhaust efficiency is poor. In order to increase the exhaust efficiency, there are cases where the operation in the facing direction of the first and second molds is stopped at the position where only the seal is in contact, and the wiring board is operated after exhausting. Thus, when the intermediate mold clamping that stops the operation of the mold during the molding operation is performed, as a result, the space to be exhausted becomes large, and the capacity of the forced exhaust means, for example, the capacity of the vacuum pump is large, and the apparatus configuration Was getting bigger.
[0010]
The present invention has been proposed in order to solve the above-described problems of the prior art, and the purpose of the present invention is to enable smooth exhaust from the mold during compression molding. An object of the present invention is to provide a mold for manufacturing a semiconductor device capable of preventing generation of voids in a resin.
[0011]
[Means for Solving the Problems]
According to the first aspect of the present invention, a first mold, a frame-shaped mold that is disposed opposite to the first mold and has an opening at the center thereof, and is fitted into the opening. A second mold including a compression mold capable of moving up and down in the opening is formed, and a cavity of the mold is formed by a space surrounded by these molds, and the first mold and the second mold are formed. In a mold for manufacturing a semiconductor device in which a molded product is disposed between the mold and the compressed mold is moved up and down to seal the molded product with a resin contained in the cavity of the frame-shaped mold. An exhaust path for forcibly discharging the gas to the outside of the mold and an opening / closing mechanism for opening and closing the exhaust path are provided in the second mold, and the exhaust path is the cavity of the frame mold Is formed in a cavity forming portion that forms the cavity of the compression mold. With a horizontal step portion in accordance with the temperature position, this step portion, wherein the exhaust hole having one end opening into the cavity is provided.
[0012]
According to the invention of claim 1 having such a configuration, since the gas in the cavity can be forcibly exhausted to the outside, the entrainment of air by the resin during molding can be suppressed. Further, by exhausting the inside of the cavity in advance, the gas existing between the granular or powdery resins can be eliminated, and the generation of voids due to the gas confined in the molten resin can be prevented. In addition, by providing the exhaust path in a frame-shaped mold that is fixed to the substrate during molding, the exhaust path does not hinder the molding operation, and the arrangement and operation of the opening / closing mechanism is easy.
[0014]
According to a second aspect of the present invention, in the first aspect of the invention, the opening / closing mechanism is a pin that is slidably fitted to a part of the exhaust hole and opens and closes the exhaust hole according to the sliding position. It is characterized by. According to the second aspect of the present invention , the exhaust hole can be opened and closed with a simple configuration in which the pin is slid. In particular, since the exhaust hole and the pin are parallel to the operation direction of the compression mold, it can be interlocked with the operation of the compression mold, and the exhaust hole can be opened and closed without driving the pin independently. .
[0015]
According to a third aspect of the present invention, there is provided a first mold, a frame-shaped mold disposed opposite to the first mold and having an opening at the center thereof, and fitted into the opening so as to be within the opening. A second mold composed of a compression mold capable of moving up and down, and a cavity of the mold is formed by a space surrounded by these molds, and the first mold and the second mold In a mold for manufacturing a semiconductor device in which a molding product is disposed between the molds, and the compression mold is moved up and down to seal the molding product with a resin contained in the cavity of the frame-shaped mold. And an opening / closing mechanism for opening and closing the exhaust path is provided in the second mold, and a part of the exhaust path is provided in the frame mold. The surface facing the first mold and formed at a position different from the position where the compression mold moves up and down. , And the said groove, characterized in that in communication with the exhaust holes formed in the frame-like mold. According to the third aspect of the present invention, an exhaust path can be provided at a location away from the ascending / descending portion of the compression mold, a larger exhaust path can be provided, and exhaust efficiency can be improved.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention (hereinafter referred to as embodiments) will be specifically described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member same as the conventional type shown in FIG.10 and FIG.11, and description is abbreviate | omitted.
[0018]
(1) First Embodiment (1-1) Configuration In this embodiment, as shown in FIGS. 1 and 2, a frame shape surrounded by a molded product 1, a frame-shaped mold 53 and a compression mold 54. The opening inside the mold forms a cavity M for resin molding. A horizontal step portion 10 a is formed in the cavity forming portion 10, which is a frame portion of the frame-shaped mold 53, according to the rising position of the compression mold 54. An exhaust hole 12 serving as an exhaust path for forcibly exhausting gas inside the cavity or gas to the outside is formed inside the frame-shaped mold 53, and one end of the exhaust hole 12 is formed at the step portion 10a. Open on the surface. As shown in the enlarged view of FIG. 3, the exhaust hole 12 includes a first exhaust hole 12a communicating with the inside of the cavity, and a second exhaust hole 12b formed by branching from the first exhaust hole 12a. It is composed of
[0019]
As shown in FIG. 3, the first exhaust hole 12a is provided with a pin 11 that slides up and down to open and close the exhaust hole 12. From the start of resin filling into the cavity to the completion of resin filling. During this time, the exhaust hole 12 is closed. The second exhaust hole 12b communicates with the outside of the mold and is connected to a forced exhaust means such as a vacuum pump (not shown).
[0020]
The pin 11 disposed in the exhaust hole 12a has a shape as shown in FIG. 3 as an example, and its base is connected to an operation mechanism (not shown). Although not shown, the pin 11 is connected to the vertical movement of the first and second molds 51 and 55 or by a predetermined operating mechanism connected to the base of the pin 11 as described above. It is configured to slide up and down in 12a.
[0021]
1 and 2, there is one exhaust hole 12, but it goes without saying that a plurality of exhaust holes 12 may be provided. Further, the exhaust hole 12 may be installed anywhere in the cavity forming portion 10 of the frame-shaped mold 53. However, as shown in FIG. It becomes easy to arrange the opening / closing mechanism.
[0022]
On the other hand, an airtight member 3 is provided on the surface of the frame-shaped mold 53 in order to ensure airtightness between the periphery of the wiring board of the molded product 1 to be processed, and the wiring of the molded product 1 By clamping the periphery of the plate with the first and second molds 51 and 55, the inside of the cavity M can be made airtight.
[0023]
(1-2) Actions / Effects A method of sealing a wiring board or the like on which a semiconductor chip is mounted with a resin using the mold of this embodiment having such a configuration is as follows.
[0024]
That is, as shown in FIG. 1, the airtight member 3 is disposed at the peripheral portion in a state where powder or granular sealing resin is accommodated in the cavity M formed by the frame-shaped mold 53 and the compression mold 54. The periphery of the molded product 1 is arranged on the frame-shaped mold 53 so that the semiconductor chip mounted on the surface (the lower surface in the drawing) of the molded product is accommodated in the cavity M. In this state, the molded product 1 is sandwiched between the first mold 51 and the second mold 52, whereby the cavity M formed by the molded product 1 and the second mold 55 is sealed. At this time, it is assumed that the compression mold 54 is in a position where the resin and the molded product do not contact each other.
[0025]
In this state, when forced exhaust means such as a vacuum pump is operated and the air in the cavity M is exhausted from the exhaust hole 12b, the inside of the cavity is decompressed and the air surrounded by the powder or granular resin is also exhausted. . After the inside of the cavity M is exhausted to a predetermined pressure, the pin 11 is raised as shown in FIG. 2 and moved to a position where the shaft portion closes the exhaust hole 12b connected to the forced exhaust means.
[0026]
Thereafter, the compression mold 54 constituting the second mold 55 is raised to the first mold 51 side to pressurize the sealing resin in the cavity M heated and melted by a heater (not shown), and to be molded The semiconductor chip arranged on the surface of the product is sealed.
[0027]
Note that the discharge timing of the air in the cavity M is preferably before the resin melts. The reason is that not only the air existing between the particles of the powdery or granular resin can be removed, but also the air can be prevented from being trapped in the melted resin. Further, after the resin has melted, forced compression may be continued even while the compression mold 54 is raised and the air in the cavity M is discharged. However, if the air is evacuated to a certain extent, there is no air escaping to the outside when the compression mold 54 is raised, so that the exhaust hole 12 can be closed.
[0028]
Thus, in this embodiment, since the exhaust hole 12 is provided in the cavity, the airtight area can be reduced compared to the case where the exhaust hole is provided outside the resin flow path. The entire size of the sealing device including the mold can be reduced. Moreover, since the airtight volume is reduced, the time for discharging gas and air can be shortened. Further, as the airtight volume is reduced, the capacity of the discharging means such as a vacuum pump can be reduced, so that the apparatus configuration can be reduced.
[0029]
Furthermore, by providing a movable pin in the exhaust hole, it is possible to reliably close the exhaust hole when resin filling in the vicinity of the exhaust hole starts, so the exhaust hole can have a necessary and sufficient cross-sectional area, Intermediate mold clamping is not required.
[0030]
(2) Second Embodiment This embodiment is a modification of the first embodiment, and as shown in FIG. 4, forced discharge of air and gas in the cavity is formed on the surface of the frame-shaped mold 20. The forced discharge path is configured to be opened and closed by an opening / closing mechanism 22 capable of closing part or all of the groove 21 through the groove 21 formed. In this case, as shown in FIG. 5 and FIG. 6 in an enlarged manner, the groove 21 communicates with an exhaust hole 23 formed, for example, vertically in the frame-shaped mold 20, and a pin 24 or the like is inserted into the exhaust hole 23. An opening / closing mechanism is provided.
[0031]
In the present embodiment having the above-described configuration, the opening / closing mechanism of the exhaust hole 23 can be configured at a position away from the sliding portion of the compression mold 54, so that a larger discharge channel can be provided. The exhaust efficiency can be improved. For example, when it is difficult to provide an exhaust hole or an opening / closing mechanism in the part due to dimensional restrictions of the molded product, or when the exhaust hole size cannot be increased, the exhaust hole and the opening / closing mechanism are connected to the sliding portion of the compression mold Therefore, a larger discharge channel can be provided, and exhaust efficiency can be improved.
[0032]
(3) Third Embodiment This embodiment is a modification of the first embodiment, and as shown in FIG. 7, the forced discharge of air and gas in the cavity is performed by sliding the frame-shaped mold 30. It is configured to perform using the exhaust hole 31 formed in the part. The position of the exhaust hole 31 is such that when the compression mold 54 is in the lowered position as shown in FIG. 7, the exhaust hole 31 communicates with the cavity, and the compression mold 54 is raised and sealed as shown in FIG. It is set so that the exhaust hole 31 is closed by the side surface of the compression mold 54 when the stop resin 58 is melted and resin filling in the vicinity of the exhaust hole 31 starts.
[0033]
According to the present embodiment having such a configuration, the exhaust hole 31 is opened and closed by moving the compression mold 54 up and down, so there is no need to provide a special opening and closing mechanism for opening and closing the exhaust hole 31. The structure can be greatly simplified.
[0034]
In the present embodiment, the exhaust hole 31 is configured to open and close so as to be “open” before molding and “closed” during molding or after molding by the lifting and lowering operation of the compression mold 54. The exhaust hole 31 can be opened and closed by a dedicated opening / closing mechanism as shown in the first and second embodiments. In that case, since the opening / closing timing can be adjusted, molding under optimum conditions becomes possible.
[0035]
(4) Fourth Embodiment This embodiment is a modification of the first embodiment. As shown in FIG. 9, the exhaust hole 41 provided with the opening / closing mechanism by the pin 11 described in the first embodiment is provided. , Provided in the compression mold 42. Also in this case, it is possible to forcibly exhaust the air inside the cavity prior to resin molding as in the first embodiment. In particular, in this embodiment, the exhaust path and its opening / closing mechanism are not provided in the frame-shaped mold part, but are provided in the central compression mold, so that only the exhaust openings necessary for the frame-shaped mold are obtained depending on the form of the molded product. This is effective when the area cannot be obtained.
[0036]
(5) Other Embodiments The present invention is not limited to the above-described embodiments, and includes the following modifications. That is, in each of the above-described embodiments, an elastic body is used as the airtight member 3 provided in the molded product 1. However, even if an elastic body is not used for the airtight member, an airtight effect can be obtained only by clamping with a mold. Sometimes. In this case, the elastic body of the airtight member can be reduced, and the mold can be simplified.
[0037]
Furthermore, in each of the above-described embodiments, the compression mold of the second mold disposed on the lower side of the first and second molds is raised to clamp the substrate of the molded product 1. However, the same effect can be obtained by lowering the first mold disposed on the upper side.
[0038]
【The invention's effect】
As described above, according to the present invention, if the air and gas inside the cavity are forcibly exhausted, the speed of the molding operation and the quality improvement of the product can be achieved, and the airtightness of only the cavity portion can be ensured. Since it is good, the amount of exhaust can be small, and it is possible to exhaust quickly, and the forced exhaust means such as a vacuum pump can be reduced in size and capacity.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the configuration of a first embodiment of a mold for manufacturing a semiconductor device according to the present invention, showing a state during exhaust from a cavity.
FIG. 2 is a cross-sectional view showing the configuration of the first embodiment of the mold for manufacturing a semiconductor device according to the present invention, and shows a state where exhaust from the cavity is stopped.
FIG. 3 is an enlarged cross-sectional view of an exhaust hole portion shown in FIG.
FIG. 4 is a cross-sectional view showing the configuration of a second embodiment of a mold for manufacturing a semiconductor device according to the present invention.
FIG. 5 is an enlarged perspective view of a groove portion shown in FIG. 4;
6 is an enlarged cross-sectional view of the groove portion shown in FIG.
FIG. 7 is a cross-sectional view showing a configuration of a third embodiment of a mold for manufacturing a semiconductor device according to the present invention, showing a state in which exhaust from the cavity is in progress;
FIG. 8 is a cross-sectional view showing the configuration of a third embodiment of a mold for manufacturing a semiconductor device according to the present invention, and shows a state where exhaust from the cavity is stopped.
FIG. 9 is a cross-sectional view showing a configuration of a fourth embodiment of a mold for manufacturing a semiconductor device according to the present invention, showing a state during exhaust from the cavity.
FIG. 10 is a cross-sectional view showing a configuration of a conventional mold for manufacturing a semiconductor device, showing a state before resin molding.
FIG. 11 is a cross-sectional view showing a configuration of a conventional mold for manufacturing a semiconductor device, and shows a resin molding completed state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Molded article 3 ... Airtight member 10 ... Cavity formation part 10a ... Step part 11 ... Pin 12 ... Exhaust hole 12a ... First exhaust hole 12b ... Second exhaust hole 20 ... Frame-shaped metal mold 21 ... Groove 22 ... Opening / closing mechanism 23 ... exhaust hole 24 ... ball valve 30 ... frame-shaped mold 31 ... exhaust hole 41 ... exhaust hole 42 ... compression mold 51 ... first mold 52 ... opening 53 ... frame-shaped mold 54 ... compression mold Mold 55 ... Second mold 56 ... Elevating mechanism 57 ... Molded product 58 ... Resin for sealing

Claims (3)

A first mold, a frame-shaped mold that is arranged opposite to the first mold and has an opening at the center thereof, and a compression mold that can be fitted into the opening and moved up and down in the opening A cavity of the mold is formed by a space surrounded by these molds,
The molded product is disposed between the first mold and the second mold, and the compressed mold is moved up and down to seal the molded product with the resin accommodated in the cavity of the frame-shaped mold. In molds for semiconductor device manufacturing,
An exhaust path for forcibly discharging the gas in the cavity to the outside of the mold and an opening / closing mechanism for opening and closing the exhaust path are provided in the second mold,
The exhaust path is provided in a cavity forming part that forms the cavity of the frame-shaped mold,
The cavity forming portion includes a horizontal step portion according to the rising position of the compression mold,
The step is provided with an exhaust hole having one end opened into the cavity. 2. The mold for manufacturing a semiconductor device according to claim 1, wherein the opening / closing mechanism is a pin that is slidably fitted to a part of the exhaust hole and opens / closes the exhaust hole depending on the sliding position. . A first mold, a frame-shaped mold that is arranged opposite to the first mold and has an opening at the center thereof, and a compression mold that can be fitted into the opening and moved up and down in the opening A cavity of the mold is formed by a space surrounded by these molds,
  The molded product is disposed between the first mold and the second mold, and the compressed mold is moved up and down to seal the molded product with the resin accommodated in the cavity of the frame-shaped mold. In molds for semiconductor device manufacturing,
  An exhaust path for forcibly discharging the gas in the cavity to the outside of the mold and an opening / closing mechanism for opening and closing the exhaust path are provided in the second mold,
  A part of the exhaust path is a groove formed on a surface opposite to the first mold in the frame-shaped mold and at a position different from a position where the compression mold moves up and down;
  The mold for manufacturing a semiconductor device, wherein the groove communicates with an exhaust hole formed in the frame-shaped mold.

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