JP7029342B2 - Mold mold, resin molding device and resin molding method - Google Patents

Description

The present disclosure relates to a molding die, a resin molding apparatus, and a resin molding method for resin-molding a work on which a plurality of chips are mounted on a substrate by exposing the chip surface.

With the spread of AI technology in recent years, a processor unit such as a GPU (Graphics Processing Unit) and an HBM (High Bandwidth Memory) are placed close to each other on a TSV-wired silicon substrate, and high density between chips is provided. SIP (System In Package) structure products connected by wiring and FPGA (Field-Programmable Gate Array) products with similar configurations are being developed. For example, many semiconductor chips such as GPU, FPGA, and HBM are mounted on a wafer as an interposer of φ300 mm, and semiconductor chips with different heights (hereinafter simply referred to as “chips”) are used for circuit protection and external. There is a need to provide a package mold to facilitate connection with peripheral circuits.

In this case, the GPU has a large mounting area such as 20 × 30 mm and includes an extremely large number of elements, and the HBM is laminated in multiple layers so that an extremely large number of storage elements are arranged, and these are high frequency. Since it operates with a signal, a large amount of heat is generated for each. For this reason, in resin molding, it is necessary to expose the surface of each chip to ensure heat dissipation. In addition, since the height of each chip is different, there is also a problem that it is vulnerable to mechanical stress and easily distorted.

In addition, when mold underfilling a work mounted in a matrix arrangement in which multiple chips are flip-chip connected on a substrate, the mold resin flows from a place with a large gap, so that the mold resin flows between the chip connected to the flip-chip and the substrate or the resin. It is difficult to fill the portion such as the gap between the chips in the direction orthogonal to the flow direction with the mold resin.

As a technology to improve the resin filling property of the mold mold, the work is clamped by the clamper, the cavity piece is filled in the cavity at the retracted position, and then the relative position of the cavity piece with respect to the clamper is moved by the mold closing operation. Mold mold using TCM (Transfer Compression Mold) that pushes back excess resin and a plate thickness adjustment mechanism (Patent Document 1: Japanese Patent Application Laid-Open No. 2013-28087) A mold mold, etc. that pressurizes the resin in the cavity with a pressurizing piece by filling the cavity with the molten mold resin from the pot by the transfer mechanism at the same height as the surface and repeating the opening and closing operations of the upper and lower molds. Has been proposed (Patent Document 2: WO2015 / 159743).

Japanese Unexamined Patent Publication No. 2013-28087 WO2015 / 159743

However, as in Patent Document 1, when the gap between the cavity pieces facing the chip is narrow, it becomes difficult for the resin to flow, and in order to prevent the resin from becoming difficult to adhere to the upper surface of the chip or the like, the cavity pieces are injected at the time of resin injection. There is a technique for improving the resin flow by increasing the amount of resin to widen the cavity space and filling the narrow part with the resin, but it is not suitable for chip exposure.
Further, as in Patent Document 2, when the mold opening / closing operation of the mold die is repeated, it is necessary to control the position of the press device with high accuracy, and the device configuration becomes complicated and sophisticated.

The disclosures applied to some of the embodiments described below are intended to solve the above problems, the purpose of which is to ensure that the surface of the chip is exposed and the resin filling property is enhanced. It is an object of the present invention to provide a moldable mold, a resin molding apparatus, and a resin molding method.

The disclosures relating to some embodiments described below comprise at least the following configurations: That is, the first mold that supports the work on which the chip is mounted, the second mold in which the cavity recess is formed facing the chip mounting portion, and the transfer mechanism that pressure-feeds the mold resin to the cavity recess. The second mold is provided with a clamper for clamping the work forming the cavity recess, and the clamper is surrounded by the clamper and is urged by the first coil spring. A chip holding piece that is constantly pressed against the chip surface in a closed state and a cavity piece that is placed around the chip holding piece and supported so as to be relatively movable between the chase and the chase. With the operation of the transfer mechanism, the cavity piece position with respect to the chip holding piece pressed against the chip surface is expanded by increasing the resin pressure against the urging of the second coil spring. It is characterized in that the mold resin is pressure-molded by relatively moving between the moved position and the position where the cavity volume is reduced due to the progress of mold closing .

According to the above configuration, when the work is clamped by the first mold and the second mold, the chip holding piece is constantly pressed against the chip surface, so that the transfer mechanism is operated to move the molten mold resin into the cavity. Even if it is filled, the surface of the chip can be reliably exposed and molded.
With the operation of the transfer mechanism, the cavity piece position with respect to the chip holding piece pressed against the chip surface is relatively moved between the position where the cavity volume is reduced by the resin pressure and the position where the cavity volume is expanded, and the mold resin is used. Is pressure-molded, so that underfill molding can be prioritized first, and then the resin filling property can be enhanced and pressure-molded so as to enhance the resin fluidity and fill the gaps between the chips.

The cavity piece is provided with a regulating portion that regulates the relative movement of at least a part of the cavity piece on the runner gate side with respect to the chip holding piece, and the cavity volume of at least a part of the cavity piece is relative to the chip holding piece pressed against the chip surface. In the position where the cavity is reduced, the mold resin is filled in the cavity recess by the operation of the transfer mechanism, and the cavity volume is moved to the position where the cavity volume is expanded by the resin pressure. When the movement in the direction of expanding the volume is restricted, the cavity piece may be relatively moved to the position where the cavity volume is reduced again by the further mold closing operation.
As a result, at least a part of the cavity piece on the runner gate side is moved from the position where the relative movement with respect to the tip holding piece is restricted to the position where the cavity volume is expanded to the position where the cavity piece is reduced again by the mold closing operation. By moving relative to each other, the resin pressure can be increased more than transfer molding and pressure molding can be performed, and voids can be reduced as much as possible to fill areas such as gaps between chips and gaps between chips and substrates that are difficult to fill with mold resin. Can be done. In particular, by reducing the volume of the cavity other than the insert holding piece, the height can be finally made the same as that of the underfill mold, so that the amount of resin used in the molded product can be reduced while improving the resin filling property of the underfill mold. You can also do it.

In the second mold, the tip holding piece is urged and supported by the first coil spring with respect to the chase, the cavity piece is urged and supported by the second coil spring , and the cavity piece is urged and supported. When the second coil spring is pushed back against the urging by the resin pressure, the movement is restricted by the stopper and the movement is preferably relative to the tip holding piece.
As a result, the increase in the pressing force of the tip holding piece by the die clamp on the tip can be released by the first coil spring , so that excessive mechanical stress does not act on the work.
Further, when the resin pressure acts on the cavity piece, the second coil spring bends and the relative position with respect to the tip holding piece changes, so that the cavity volume can be made variable. Therefore, when the mold resin is received in the cavity recess with the cavity piece expanding the cavity volume and the movable position is restricted by the stopper, the relative position with respect to the tip holding piece moves downward due to the further mold closing operation. Therefore, it is possible to reduce the cavity volume and apply a higher resin pressure than normal transfer molding to perform pressure molding.

It is preferable that the cavity piece moves relative to the height of the lower surface of the chip pressed against the chip holding piece by the mold closing operation, and moves relative to the height position of the upper surface of the chip by the resin pressure.
As a result, when the transfer mechanism is operated to fill the cavity recess with the mold resin, the position of the cavity piece is relatively moved, so that the mold underfill of the chip connected to the flip chip can be preferentially performed. When resin pressure is applied, the space inside the cavity recess can be expanded to facilitate filling of the gap with the mold resin.
In addition, if the final mold closing position of the cavity piece is suppressed below the height position of the upper surface of the chip, the resin pressure can be applied with a higher pressing force than normal transfer molding, so that voids can be reduced as much as possible and it is useless. Resin molding can be performed by reducing the amount of resin.

In the chip holding piece, the chip holding pieces may be arranged so as to face a plurality of chips. As a result, by pressing the chip surface for each chip on which the chip pressing piece faces, it is possible to reliably perform exposure molding.

It is preferable that a decompression space is formed in the mold by the mold closing operation by the first mold and the second mold. As a result, air bubbles mixed in the mold resin filled in the cavity recess can be removed by vacuum suction to improve the molding quality.

It is preferable that the film is attracted and held on the clamp surface of the second mold including the cavity recess, and is pressed against the chip surface by the chip holding piece via the film. As a result, when the tip holding piece is pressed against the tip, the film can be used as a cushioning material to protect the tip surface, and the clamper, the tip holding piece, and the cavity piece move relative to each other by the mold closing operation, and the volume of the cavity recess is reached. Even if the mold resin changes, the mold resin does not leak and the mold maintenance can be facilitated.

The clamper may be provided with an overflow cavity for accommodating the mold resin overflowing from the cavity recess.
As a result, the mold resin filled in the cavity recess is pressurized and overflows, so that the unfilled area of the mold resin can be eliminated as much as possible and the molding quality can be improved.

In the resin molding apparatus, by providing the molding die described in any of the above, the surface of the chip is surely exposed and the resin filling property is improved, thereby improving the molding quality and the productivity. Can be done.

This is a resin molding method in which the chip is exposed to the workpiece on which the chip is mounted and transferred, and the process of closing the mold and clamping the workpiece with a clamper that forms the side of the cavity and the bottom of the cavity are formed. The tip holding piece is urged against the chase by the first coil spring , is placed around the tip holding piece while being pressed against the chip surface, and is urged by the second coil spring provided between the chase and the chase. The process of relatively moving the cavity piece to the position where the cavity volume is reduced, the process of operating the transfer mechanism to pressure-feed the molten mold resin into the cavity, and the resin pressure fully filled in the cavity. The process of retracting the cavity piece to the position where the cavity volume is expanded against the urging of the second coil spring and filling the mold resin, and the movement of the cavity piece to the position where the cavity volume is expanded are restricted. This includes a step of performing the mold closing operation of the mold while keeping the mold closed, moving the cavity piece relative to a position where the cavity volume is reduced by the progress of mold closing, pressurizing the resin in the cavity, and pushing it out of the cavity. It is a feature.

By using the resin molding method described above, even if the transfer mechanism is operated to fill the cavity with the molten mold resin, the surface of the chip can be reliably exposed and molded, and the cavity piece can control the cavity volume. Priority is given to the underfill mold at the reduced first position, and then the cavity piece is retracted to the second position where the cavity volume is expanded to increase the resin fluidity and increase the resin filling property so as to fill the gap between the chips. Can be pressure formed.
In addition, by moving the cavity piece relative to the first position again to pressurize the resin inside the cavity and pushing it out of the cavity, the resin pressure can be applied with a higher pressure than normal transfer molding, so voids are possible. It is possible to reduce the amount of resin in the final molded product and reduce the amount of resin that is wasted in the final molded product.
Therefore, the workpiece on which the insert is mounted can be subjected to transfer molding by exposing the insert with an underfill mold.

By relatively moving the cavity piece to the first position, which is the height position of the lower surface of the chip, and molding the cavity piece, the resin filling property of the underfill mold can be improved, and the amount of wasteful resin in the final molded product can be reduced. Can be resin molded.

By using the mold mold, the resin molding device, and the resin molding method, the surface of the chip can be reliably exposed to improve the resin filling property and mold can be performed.

It is a plan view and a front view of the work before molding used in 1st Example, and the front view of the work after molding. It is a partial cross-sectional view of the mold mold which concerns on 1st Example. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial plan view of the upper mold. It is a partial plan view of the lower mold. FIG. 3 is an enlarged plan view of an upper mold surface including a cavity recess used in the second embodiment. It is a partial cross-sectional view of the mold mold which concerns on 2nd Example. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG. It is a partial cross-sectional view of the mold mold following FIG.

Hereinafter, an embodiment for carrying out the invention will be described in detail with reference to the accompanying drawings. The term "mold mold" refers to the upper mold and the lower mold supported by the mold base, respectively, and refers to the mold excluding the mold opening / closing mechanism (pressing device). In addition, when referring to a resin molding device, it is a device equipped with at least a mold and a mold opening / closing mechanism (pressing device such as an electric motor, screw shaft, toggle link mechanism, etc .; not shown) that opens and closes the mold, and is further automated. For this purpose, it is a device provided with a resin transfer device or a work transfer device, and a work unloading device after molding. In the case of transfer molding, it is assumed that a transfer mechanism for operating the plunger inserted in the pot, a decompression mechanism for forming a decompression space in the mold when the mold is closed, and the like are provided. Hereinafter, the configuration of the mold mold will be mainly described. Further, the work W uses a resin for an interposer substrate (semiconductor wafer, resin substrate, etc.) on which a large number of semiconductor chips such as a processor and HBM are mounted, and an interposer substrate (semiconductor wafer, resin substrate, etc.) on which a MEMS chip or the like is mounted. It is supposed to be molded. As an example, the mold mold will be described as a movable mold for the lower mold and a fixed mold for the upper mold, but the upper mold may be a movable mold and the lower mold may be a fixed mold, or both may be a movable mold.

The work W is composed of a substrate K and a chip T, and the chip T is electrically connected to the substrate K (flip chip connection or the like). The chip T includes not only semiconductor chips but also functional parts such as MEMS chips. The above-mentioned semiconductor chip, MEMS chip, and the like have been exemplified as the chip T that requires exposure, but the chip T is not limited to these, and can be applied even when the surface of a heat sink or an image pickup device is exposed, for example. The chip T refers to the entire mounted component of the substrate K that needs to be exposed. Therefore, the chip T is not necessarily connected to the flip chip.
In the following, a case where the chip T is sandwiched and molded by using the film F will be described, but the film F is not necessarily a necessary member and may be omitted.

[First Example]
FIG. 1 illustrates a case where mold underfilling is performed using a strip-shaped strip substrate (rectangular substrate) having a size of 100 mm × 300 mm as the work W.
As shown in FIG. 1A, the chips T are mounted on the substrate K in a matrix arrangement. As shown in FIG. 1B, the chip T is flip-chip connected to a terminal connection portion formed on the substrate K via solder bumps.
FIG. 1C shows the work W after molding. Each chip T arranged in the matrix is mold underfilled and molded by the mold resin R up to the gap between the chips. Although the example of 5 lines is shown in FIG. 1, an example of 3 lines is shown by omitting from FIG. Note that the rows and columns are examples and are not limited thereto.

Next, a configuration example of the mold mold 1 will be described with reference to FIGS. 2, 9 and 10. In FIG. 2, the upper mold 3 (second mold) is formed with a cavity recess 4 facing the chip mounting portion. The lower mold 2 (first mold) is provided with a transfer mechanism 5 in which a work W on which the chip T is mounted is supported and the mold resin R is pressure-fed to the cavity recess 4.

First, the configuration of the lower mold 2 will be described. A lower die chase 2a is provided on a lower die base (not shown). The lower die insert 2b and the lower die center insert 2c are supported on the lower die chase 2a. A cylindrical pot 2d in which a pot hole (through hole) is formed is assembled to the lower center insert 2c (one pot 2d is drawn in FIG. 2, but a plurality of pots 2d are drawn in the direction perpendicular to the paper surface). exist.). A plunger 5a is inserted in the pot 2d, and the plunger 5a is moved up and down by the trans-affa mechanism 5. The plunger 5a is floatingly supported by, for example, a coil spring provided in the transfer mechanism 5. The plunger 5a may be supported by a hydraulic uniform pressure circuit instead of being supported by a coil spring.

Further, the lower mold insert 2b is engraved with a work mounting portion 2e on which the work W is mounted. The work W may be suction-held when it is placed on the work mounting portion 2e. The work W may be positioned by a clamp claw or the like while being placed on the work mounting portion 2e or the lower mold insert 2b. An annular sealing material 2f is provided on the outer peripheral edge of the lower die chase 2a. The sealing material 2f is sandwiched between the sealing material 2f and the upper mold chase 3a, which will be described later, and sealed to form a closed space in the mold mold 1. Further, the lower chase 2a is provided with a suction path 2g connected to a closed space, and is connected to a suction mechanism (not shown). A decompression space is formed in the mold 1 by operating a suction mechanism (not shown) in a state where the seal 2f between the upper mold 3 and the lower mold 2 is in contact with each other. An example of the plane layout of the lower mold 2 is shown in FIG. The work W is mounted on the work mounting portion 2e, and the side surface of the lower center insert 2c is mounted as a positioning guide. It should be noted that a positioning pin (not shown) may be inserted into a hole on the outer periphery of the work for positioning.

Next, the configuration of the upper mold 3 will be described. In FIG. 2, an upper die chase 3a is provided on the upper die base (not shown). In the upper die chase 3a, the upper die clamper 3b is suspended and supported by a third coil spring 3c (third urging means). The upper die clamper 3b clamps the work W (outer circumference of the substrate K) mounted on the work mounting portion 2e of the lower die 2. A through hole 3d is provided in a portion of the upper clamper 3b corresponding to the bottom of the cavity. In the through hole 3d, a tip holding piece 3e that is constantly pressed against the chip surface in a closed state and an upper die cavity piece 3f are inserted around the tip holding piece 3e so as to be relatively movable. The chip holding pieces 3e are arranged so as to face the chip T. The cavity recess 4 is formed by the upper die clamper 3b, the tip holding piece 3e, and the upper die cavity piece 3f.

Specifically, the upper die cavity piece 3f is suspended and supported on the support plate 3g. The support plate 3g is suspended and supported by a second coil spring 3h (second urging means) with respect to the upper die chase 3a. Further, the support block 3i is integrally supported on the lower surface of the support plate 3g, and the upper end portion of the suspension pin 3j is locked and suspended from the support block 3i. A tip holding piece 3e is connected to the hanging lower end of the hanging pin 3j. The hanging pin 3j is suspended and supported in a state where the pin head (upper end portion) is pushed down by the first coil spring 3k (first urging means) provided elastically in the support block 3i. Therefore, the support plate 3g is suspended and supported from the bottom surface (first stopper 3m) of the upper die chase 3a in a state where the second coil spring 3h is extended. Further, the tip holding piece 3e is suspended and supported apart from the lower end surface (second stopper 3n) of the support block 3i by the elasticity of the first coil spring 3k. The movable range of the upper die cavity piece 3f is narrower than the movable range of the tip holding piece 3e. That is, the movable range in which the support plate 3g is restricted to the bottom of the upper chase 3a is narrower than the movable range in which the tip holding piece 3e is restricted to the stopper 3m.

As described above, since the increase in the pressing force of the tip holding piece 3e against the tip T in closing the mold is absorbed by the bending of the first coil spring 3k, excessive mechanical stress does not act on the work W. Further, since it is clamped via the film F described later, there is less mechanical stress.
Further, when the resin pressure acts on the upper die cavity piece 3f, the second coil spring 3h bends and absorbs the resin pressure, so that the relative position with respect to the tip holding piece 3e changes, so that the cavity volume can be made variable.
Therefore, when the mold resin R is received in the cavity recess 4 with the upper die cavity piece 3f expanding the cavity volume and the movable position of the upper die cavity piece 3f is restricted by the first stopper 3m, the mold closing operation is further performed. As a result, it can move downward relative to the tip holding piece 3e to reduce the cavity volume and apply a higher resin pressure than normal transfer molding to perform pressure molding.

In FIG. 2, a sealing material 3p is provided between the outer wall surface of the upper die clamper 3b and the inner wall surface of the upper die chase 3a. Further, the upper die chase 3a is provided with a suction path 3t, which is connected to a suction mechanism (not shown). By operating the suction mechanism in the mold closed state, a decompression space is formed in the mold mold 1. Further, on the clamp surface of the upper mold clamper 3b, the upper mold cal 3q and the upper mold runner gate 3r (resin path) are engraved at positions with respect to the lower mold center insert 2c (see FIG. 9). As shown in FIG. 9, the tip end portion of the upper die runner gate 3r is connected to the cavity recess 4 (the outer peripheral edge portion of the upper die cavity piece 3f).

The film F is adsorbed and held on the upper clamp surface including the cavity recess 4 and the resin path connected to the cavity recess 4. The film F may be a long continuous film or a film cut into strips (sheet-fed film). As the film F, for example, a release film having a thickness of about 50 μm and having heat resistance is used. The release film is easily peeled off from the mold surface and has flexibility and extensibility, for example, PTFE, ETFE, PET, FEP film, fluorine-impregnated glass cloth, polypropylene film, polyvinylidine chloride, etc. A single-layer or multi-layer film containing the above as a main component is preferably used. As a result, the surface of the chip T can be covered to absorb variations in height, and the mold resin R can be prevented from entering the surface of the chip for exposure molding.

Further, the film F may be a filter film-like porous film that does not allow moisture or the like to pass through and allows moisture or air to escape, for example, Poaflon (trade name), a microporous film, or the like. Further, in the case of a porous film, air can be released without allowing the mold resin R to infiltrate, so that the molding quality is improved by releasing the air and the generated gas mixed in the mold resin R under a reduced pressure environment. be able to.

Next, the resin molding operation using the work W will be described with reference to FIGS. 2 to 8. FIG. 2 shows a state in which the mold 1 is opened. The film F is adsorbed and held on the upper die clamp surface of the upper die 3. A solid resin (resin tablet) is supplied into the pot 2d of the lower mold 2, and the work W is positioned and supported by the work mounting portion 2e. The work W and the mold resin R may be carried in at the same time by a loader or the like (not shown), or may be carried in individually. Further, the support plate 3g and the tip holding piece 3e are suspended and supported at the lower end position of the movable range.

FIG. 3 shows a state in which the mold closing operation of the mold mold 1 progresses, the lower mold 2 moves upward with respect to the upper mold 3, and the sealing material 2f is clamped by the upper mold chase 3a and the lower mold chase 2a. By a suction operation by a suction mechanism (not shown), air is sucked from the suction paths 2g and 3t in the mold 1 in which the closed space is formed, and a decompression space is formed. Further, as the mold closing progresses, the chip holding piece 3e is pressed against the surface of the chip T via the film F.

FIG. 4 shows a state in which the lower mold 2 is further moved upward and the mold is closed. The upper die clamper 3b abuts on the work W (outer circumference of the substrate K) and the lower die insert 2b via the film F and clamps. Further, although the pressing force of the tip holding piece 3e is increased against the tip T, excessive stress does not act on the tip T because the first coil spring 3k bends. Along with this, the height of the lower end portion of the upper die cavity piece 3f is relatively lowered to the height position of the terminal (solder bump) of the chip T. As a result, the resin injection height in the cavity can be made substantially the same regardless of the presence or absence of the tip T.

In this state, as shown in FIG. 5, the transfer mechanism 5 operates to raise the plunger 5a, and the mold resin R heated and melted in the pot 2d is passed through the upper die cal 3q and the upper die runner gate 3r into the cavity recess 4. Pressure feed to. The mold mold 1 is heated by a heater (not shown). At this time, since the height of the lower end of the upper die cavity piece 3f is at the height position (first position) of the terminal (solder bump) of the chip T, the mold resin R is from the gate side regardless of the presence or absence of the chip. It is injected sequentially. FIG. 5 shows a state in which the cavity recess 4 is not yet fully filled with the mold resin R. Although the upper movement of the lower mold 2 is temporarily stopped, it may continue to rise. The height of the first position is the height of the terminal (solder bump) of the chip T, but if the force of the resin passing between the bumps is larger than the force of flowing other than the bumps, it will be difficult for the resin to flow to the bumps. The height of the position may be set narrower so that the bumps flow preferentially.

Next, as shown in FIG. 6, since the inside of the cavity recess 4 is filled with the mold resin R by the transfer mechanism 5, the resin pressure for the transfer operation increases, and the upper die cavity piece 3f and the support plate 3g supporting the upper cavity piece 3f have a resin pressure. Is pushed back upward against the urging of the second coil spring 3h. Then, the support plate 3g is pushed back to a position (second position) where the support plate 3g abuts on the first stopper 3m (bottom surface of the upper die chase 3a).
Next, as shown in FIG. 7, the upper die clamper 3b pushes up against the urging of the third coil spring 3c by the further upward movement of the lower die 2. The work W mounted on the lower insert 2b rises and pushes up the tip holding piece 3e, but the cavity piece 3f remains fixed and cannot rise. As a result, the upper die cavity piece 3f moves downward relative to the tip holding piece 3e and presses the mold resin R. At this time, the mold resin R overflowing due to the reduction in the cavity volume pushes down the plunger 5a via the resin path (upper mold runner gate 3r, upper mold cal 3q) and is returned into the pot 2d. Alternatively, the mold resin R may overflow into an overflow cavity (not shown) provided on the upper clamper 3b by reducing the cavity volume.

As a result, the resin pressure can be increased even in a narrow gap between the chips T to improve the filling property. At this time, the pressing force on the tip T by the tip holding piece 3e is increased, but excessive stress does not act on the tip T because the first coil spring 3k bends. The height of the lower end surface of the upper die cavity piece 3f may be the height position (first position) of the terminal (solder bump) of the chip T or the surface of the chip T. In this state, the upward movement of the lower mold 2 is stopped, and the mold resin R is heat-cured while maintaining the resin pressure to hold the pressure.
Since the tip holding piece 3e does not hit the second stopper 3n, the increase in the pushing pressure acting on the tip T is absorbed by the bending of the first coil spring 3k. Further, the third coil spring 3c that suspends and supports the upper die clamper 3b is compressed and continues to bend while the lower die 2 continues to move upward.

Next, as shown in FIG. 8, when the molding operation is completed, the mold 1 is opened, and the film F adsorbed and held on the clamp surface of the upper mold 3 is peeled off and replaced. Further, since the work W and the unnecessary resin remain on the clamp surface of the lower mold 2, they are carried out by an unloader or the like (not shown).

As described above, when the work W is clamped by the upper die 3 and the lower die 2, the tip holding piece 3e is constantly pressed against the tip surface, so that the transfer mechanism 5 is operated to move the molten mold resin R into the cavity. The surface of the chip T can be reliably exposed and molded even when the chip T is filled.
Further, the mold resin is operated by the transfer mechanism 5 at the first position where the upper die cavity piece 3f is reduced in cavity volume with respect to the tip holding piece 3e pressed against the chip surface by closing the mold mold 1. Since R is injected into the cavity and the height of the upper die cavity piece 3f is substantially the same as the underfill height of the tip T, the mold resin R is sequentially filled from the gate toward the gap around it, and the cavity recess is formed. 4 can be fully filled.
Further, the relative movement of the upper mold cavity piece 3f is restricted, and the mold resin R is pressure-molded by relatively moving the upper mold cavity piece 3f to the first position where the cavity volume is reduced again by the further mold closing operation. Therefore, the resin pressure can be increased more than transfer molding and pressure molding can be performed, and voids can be reduced as much as possible to fill the gaps between the chips T and the gaps between the chips T and the substrate K where the resin is difficult to fill. can. In particular, by reducing the volume of the cavity other than the tip holding piece 3e, the height can be finally made the same as that of the underfill mold, so that the filling property of the mold resin R can be improved and the amount of resin used can be reduced. ..

[Second Example]
Next, as the work W, a mold mold for performing mold underfill using, for example, a circular carrier substrate (semiconductor wafer) having a diameter of 300 mm will be illustrated. As an example of the chip T so as to correspond to the plan view of the upper die 3 (FIG. 11A), for example, a GPU having a size of 20 × 30 mm and a large number of semiconductor chips in which HBMs are arranged in close proximity to the GPU are located on the circular carrier substrate K. It is a board for FPGA mounted. The chip T is flip-chip connected to a terminal connection portion formed on the substrate K via solder bumps (see FIG. 12).
In the first embodiment, the cavities can be arranged between the chips T in the chips T arranged in the matrix, but in the second embodiment, the cavities are arranged between the chips T because the spaces between the chips are narrow and arranged next to each other. Pieces cannot be placed.

Next, a configuration example of the mold mold 1 will be described with reference to FIGS. 11 and 12. The same member as the mold mold 1 according to the first embodiment shall be assigned the same number and the description shall be incorporated. It should be noted that FIGS. 12 to 17 are schematic views, and are accurate unless the upper die cavity piece 3f existing around the tip holding piece 3e of the upper die 3 (particularly on the opposite side to the upper die runner gate) is required for explanation. Not shown in.
In FIG. 12, the upper mold 3 (second mold) is formed with a cavity recess 4 facing the chip mounting portion. Further, a work W on which the tip T is mounted is supported on the lower mold 2 (first mold), and a transfer mechanism 5 for pressure-feeding the mold resin R to the cavity recess 4 is provided.

First, the configuration of the lower mold 2 will be described. In FIG. 12, a lower mold chase 2a is provided on a lower mold base (not shown). The lower die chase 2a supports a first lower die insert 2b1, a second lower die insert 2b2, and a lower die center insert 2c. A cylindrical pot 2d in which a pot hole (through hole) is formed is assembled to the lower center insert 2c (one pot 2d is drawn in FIG. 12, but a plurality of pots 2d are drawn in the direction perpendicular to the paper surface). It may exist.). A plunger 5a is inserted in the pot 2d, and the plunger 5a is moved up and down by the trans-affa mechanism 5. The plunger 5a is floatingly supported by, for example, a coil spring provided in the transfer mechanism 5. The plunger 5a may be supported by a hydraulic uniform pressure circuit instead of being supported by a coil spring.

Further, the work W is placed on the first lower mold insert 2b1. The upper end surfaces of the second lower mold insert 2b2 and the lower mold center insert 2c are formed higher than the first lower mold insert 2b1, and the work W is mounted on the upper surface of the first lower mold insert 2b1. The work W may be suction-held when placed on the first lower mold insert 2b1. Further, a flange-shaped work holding portion 2d1 is formed at the upper end portion of the pot 2d so as to hold the circular work W and position it on the upper surface of the first lower mold insert 2b1. The work holding portion 2d1 may also serve as a resin path (lower type runner gate). The work W may be positioned by a clamp claw or the like while being placed on the lower mold insert 2b. The lower die chase 2a is provided with a sealing material 2f. The sealing material 2f is sandwiched between the upper mold chase described later and a closed space is formed in the mold. Further, the lower type chase 2a is provided with a suction path 2g, which is connected to a suction mechanism (not shown). By operating the suction mechanism in the closed state of the mold, a decompression space is formed in the mold.

Next, the configuration of the upper mold 3 will be described. In FIG. 12, an upper die chase 3a is provided on the upper die base (not shown). In the upper die chase 3a, the upper die clamper 3b is suspended and supported by a third coil spring 3c (third urging means). The upper die clamper 3b clamps the work W (outer circumference of the substrate K) placed on the first lower die insert 2b1 of the lower die 2 and the upper surface of the second lower die insert 2b2. The lower surface portion of the fixed cavity piece 3s forming the cavity recess 4 of the upper type clamper 3b is the pressurized cavity portion 3b2 that pressurizes the mold resin R, and the outside of the pressurized cavity portion 3b2 is the cavity recess 3b1 in the clamper. An overflow cavity (not shown) may be formed in the cavity recess 3b1 in the clamper.

As shown in FIG. 11A, a through hole 3d is provided in a portion corresponding to the cavity bottom of the upper type clamper 3b. In the through hole 3d, a tip holding piece 3e that is constantly pressed against the chip surface in a closed state and an upper die cavity piece 3f are inserted around the tip holding piece 3e so as to be relatively movable. The chip holding pieces 3e are arranged so as to face the chip T. The cavity recess 4 is formed by the upper die clamper 3b, the tip holding piece 3e, and the upper die cavity piece 3f. In FIG. 11A, the area surrounding the tip holding piece 3e is all the upper die cavity piece 3f, but as shown in FIG. 11B, the upper die cavity piece 3f that can move relative to the tip holding piece 3e is a runner. It may be provided at least in a part necessary for resin flow on the gate side, and the other may be a pressurized cavity portion 3b2 of the fixed cavity piece 3s. The cavity recess 4 is formed by the upper mold clamper 3b, the tip holding piece 3e, the upper die cavity piece 3f, and the pressure cavity portion 3b2.

In FIG. 12, the fixed cavity piece 3s is supported and fixed to the bottom surface of the upper die chase 3a. The first hanging pin 3j1 is inserted into the through hole in the fixed cavity piece 3s, and the tip holding piece 3e is suspended and supported on the lower surface side of the fixed cavity piece 3s at the lower end of the pin. Further, a first coil spring 3k (first urging means) is elastically provided between the upper end portion of the first suspension pin 3j1 and the bottom surface of the upper die chase 3a.
Similarly, the second hanging pin 3j2 is inserted into the through hole in the fixed cavity piece 3s, and the upper cavity piece 3f is suspended and supported on the lower surface side of the fixed cavity piece 3s at the lower end of the pin. In FIG. 12, the upper die cavity piece 3f shows only a part of the gate side where the mold resin R first flows in the cavity recess 4, and only a part of the upper die cavity piece 3f up to the tip holding piece 3e. It is shown in the figure. Further, a second coil spring 3h (second urging means) is elastically provided between the upper end portion of the second hanging pin 3j2 and the bottom surface of the upper die chase 3a.

Therefore, the upper die cavity piece 3f is suspended and supported apart from the bottom surface (first stopper 3m) of the fixed cavity piece 3s. Further, the tip holding piece 3e is suspended and supported apart from the lower end surface (second stopper 3n) of the fixed cavity piece 3s. The movable range of the upper die cavity piece 3f is wider than the movable range of the tip holding piece 3e. That is, the movable range in which the upper die cavity piece 3f is restricted by the first stopper 3m is wider than the movable range in which the tip holding piece 3e is restricted by the second stopper 3n.

As described above, since the increase in the pressing force of the tip pressing piece 3e at the time of closing the mold is absorbed by the bending of the first coil spring 3k, excessive mechanical stress does not act on the work W. Further, since the chip T is clamped via the film F, there is less mechanical stress.
Further, when the resin pressure acts on the upper die cavity piece 3f, the second coil spring 3h bends and absorbs the resin pressure, so that the relative position with respect to the tip holding piece 3e changes, so that the cavity volume can be made variable.
Therefore, when the mold resin R is received in the cavity recess 4 with the upper die cavity piece 3f expanding the cavity volume and the movable position of the upper die cavity piece 3f is restricted by the first stopper 3m, the mold closing operation is further performed. As a result, it can move downward relative to the tip holding piece 3e to reduce the cavity volume and apply a higher resin pressure than normal transfer molding to perform pressure molding.

In FIG. 12, a sealing material 3p is provided between the outer wall surface of the upper die clamper 3b and the inner wall surface of the upper die chase 3a. Further, the upper die chase 3a is provided with a suction path 3t, which is connected to a suction mechanism (not shown). By operating the suction mechanism in the mold closed state, a decompression space is formed in the mold mold 1. Further, the upper die cal 3q and the upper die runner gate 3r (resin path) are engraved on the clamp surface of the upper die clamper 3b at positions with respect to the lower die center insert 2c. The tip of the upper die runner gate 3r is connected to the outer peripheral portion of the upper die cavity piece 3f. The film F is adsorbed and held on the upper clamp surface including the cavity recess 4 and the resin path connected to the cavity recess 4. It is the same as in the first embodiment that the film F may be a long continuous film or a film cut into strips.

Next, the resin molding operation using the work W will be described with reference to FIGS. 12 to 17.
FIG. 12 shows a state in which the mold 1 is opened. The film F is adsorbed and held on the upper die clamp surface of the upper die 3. The work W is positioned and supported on the upper surface of the first lower mold insert 2b1. As shown in FIG. 13, the work W is placed on the upper surface of the first lower mold insert 2b1 with the outer peripheral edge surrounded by the lower mold center insert 2c and the second lower mold insert 2b2, and the work holder of the pot 2d is held down. The portion 2d1 is positioned by superimposing the portion 2d1 on the upper surface of the work W (board K). Further, a solid resin (mold resin R: resin tablet) is supplied into the pot 2d. The work W and the mold resin R may be carried in at the same time by a loader or the like (not shown), or may be carried in individually. Further, the upper die cavity piece 3f and the tip holding piece 3e are suspended and supported at the lower end position of the movable range. At this time, the suction operation may be started from the suction path 3t of the upper type chase 3a and the suction path 2g of the lower type chase 2a.

FIG. 14 shows a state in which the mold closing operation of the mold mold 1 progresses, the lower mold 2 moves upward with respect to the upper mold 3, and the sealing material 2f is clamped by the upper mold chase 3a and the lower mold chase 2a. A decompression space is formed by sucking air from the suction paths 2g and 3t in the mold 1 in which the closed space is formed by the suction operation by the suction mechanism (not shown). Further, as the mold closing operation progresses, the chip holding piece 3e is pressed against the surface of the chip T via the film F.

Further, when the lower mold 2 further moves upward and the mold closing progresses, the upper mold clamper 3b passes through the film F to the work W (outer circumference of the substrate K) and the lower mold clamp surface (first lower mold insert 2b1 and second lower mold). It comes into contact with the insert 2b2) and is clamped. Further, although the pressing force of the tip holding piece 3e is increased against the tip T, excessive stress does not act on the tip T because the first coil spring 3k bends. Along with this, as shown in FIG. 14, the height of the lower end portion of the upper die cavity piece 3f is relatively lowered to the height position of the terminal (solder bump) of the chip T.

In this state, the transfer mechanism 5 operates, the plunger 5a rises, and the molded resin R melted in the pot 2d is passed through the resin path between the upper die cal 3q, the upper die runner gate 3r, and the work holding portion 2d1. It is pressure-fed into the recess 4. At this time, since the height of the lower end of the upper die cavity piece 3f is at the height position (first position) of the terminal (solder bump) of the chip T, the mold resin R is from the gate side regardless of the presence or absence of the chip. It is injected sequentially. FIG. 14 shows a state in which the cavity recess 4 is not yet filled. Although the upper movement of the lower mold 2 is temporarily stopped, it may continue to rise.

Next, as shown in FIG. 15, since the transfer operation by the transfer mechanism 5 is completed and the inside of the cavity recess 4 is filled with the mold resin R, the resin pressure is increased by the transfer operation, and the upper die cavity piece 3f is subjected to the resin pressure. It is pushed back upward against the urging of the two-coil spring 3h. Then, the upper die cavity piece 3f is pushed back to a position (second position) where it abuts on the first stopper 3m (bottom surface of the fixed cavity piece 3s), and in this figure, it may be located above the upper surface of the tip T. Is shown. As shown in FIG. 16, due to the further upward movement of the lower die 2, the pressurized cavity portion 3b2 of the upper die cavity piece 3f and the fixed cavity piece 3s moves downward relative to the tip holding piece 3e, and the mold resin R Press. At this time, the mold resin R overflowing due to the reduction in the cavity volume pushes down the plunger 5a through the resin path (upper mold runner gate 3r, work holding portion 2d1, upper mold cal 3q) and is returned into the pot 2d. Alternatively, the mold resin R may overflow into the overflow cavity provided in the upper clamper 3b by reducing the cavity volume. In Example 1, the resin thickness was finally formed at the height of the bump, but in Example 2, the resin thickness is formed up to the surface of the chip T. FIG. 17 is another embodiment, and like the first embodiment, all of the upper die cavity pieces 3f except the tip holding piece 3e in the cavity recess 4 are shown.

As a result, the resin pressure can be increased even in a narrow gap between the chips T to improve the filling property. At this time, the pressing force on the tip T by the tip holding piece 3e is increased, but excessive stress does not act on the tip T because the first coil spring 3k bends. The height of the lower end surface of the upper die cavity piece 3f may be the height position (first position) of the terminal (solder bump) of the chip T or the surface of the chip. In this state, the upward movement of the lower mold 2 is stopped, and the mold resin R is heat-cured and held in pressure while maintaining the resin pressure.
Since the tip holding piece 3e does not hit the second stopper 3n, the increase in the pushing pressure acting on the tip T is absorbed by the bending of the first coil spring 3k. Further, the third coil spring 3c that suspends and supports the upper die clamper 3b is compressed and continues to bend while the lower die 2 continues to move upward from the time when the lower die 2 is clamped.

When the molding operation is completed, the mold 1 is opened, and the film F adsorbed and held on the clamp surface of the upper mold 3 is peeled off and replaced. Further, since the work W and the unnecessary resin remain on the clamp surface of the lower mold 2, they are carried out by an unloader or the like (not shown).

As described above, when the work W is clamped by the upper die 3 and the lower die 2, the tip holding piece 3e is constantly pressed against the tip surface, so that the transfer mechanism 5 is operated to move the molten mold resin R into the cavity. The surface of the chip T can be reliably exposed and molded even when the chip T is filled.
Further, with respect to the chip holding piece 3e pressed against the surface of the chip by closing the mold of the mold 1, the upper die cavity piece 3f is moved from the first position where the cavity volume is reduced to accompany the operation of the transfer mechanism 5. The cavity recess 4 can be filled while promoting the filling of the mold resin R from the runner gate toward the gap around the runner gate by relatively moving the cavity volume to the expanded second position.
Further, the relative movement of the upper die cavity piece 3f is restricted, and the mold resin R is pressure-molded by relatively moving the upper die cavity piece 3f to the first position where the cavity volume is reduced again by a further mold closing operation. Therefore, the resin pressure can be increased more than the transfer molding and pressure molding can be performed, and the voids can be reduced as much as possible to fill the gaps between the chips T and the gaps between the chips T and the substrate K where the resin is difficult to fill. .. In particular, by reducing the volume of the cavity other than the tip holding piece 3e, the height can be finally made the same as that of the underfill mold, so that the filling property of the mold resin R can be improved and the amount of resin used can be reduced. ..

In the above-described embodiment, the transfer mechanism 5 is provided in the lower mold 2, but may be provided in the upper mold 3. Further, although the cavity recess 4 is provided in the upper mold 3, it may be provided in the lower mold 2.

W Work T Chip K Board R Mold resin F Film 1 Mold mold 2 Lower mold 2a Lower mold chase 2b Lower mold insert 2b1 First lower mold insert 2b2 Second lower mold insert 2c Lower mold center insert 2d Pot 2d 1 Work holder 2e Work mounting part 2f, 3p Sealing material 2g, 3t Suction path 3 Upper type 3a Upper type chase 3b Upper type clamper 3b1 Clamper inner cavity recess 3b2 Pressurized cavity part 3c Third coil spring 3d Through hole 3e Chip holding piece 3f Upper type Cavity piece 3f1 Fixed cavity piece 3f2 Movable cavity piece 3g Support plate 3h Second coil spring 3i Support block 3j Hanging pin 3j1 First hanging pin 3j2 Second hanging pin 3k First coil spring 3m First stopper 3n Second stopper 3q Upper type coil 3r Upper type runner gate 3s Fixed cavity piece 4 Cavity recess 5 Transfer mechanism 5a Plunger

Claims (11)

A first mold that supports a workpiece on which a chip is mounted, a second mold in which a cavity recess is formed facing the chip mounting portion, and a transfer mechanism that pressurizes a mold resin into the cavity recess. It is a molded mold equipped with
The second mold is arranged surrounded by a clamper that clamps the work forming the cavity recess and the clamper, and is urged by the first coil spring to be constantly pressed against the chip surface in a closed state. It is provided with a tip holding piece to be hit and a cavity piece placed around the tip holding piece and supported so as to be relatively movable via a second coil spring .
Along with the operation of the transfer mechanism, the cavity piece position with respect to the chip holding piece pressed against the chip surface was expanded in the cavity volume against the urging of the second coil spring due to the increase in resin pressure . A mold mold characterized in that the mold resin is pressure-molded by relatively moving between the position and the position where the cavity volume is reduced due to the progress of mold closing . The cavity piece is provided with a regulating portion that regulates the relative movement of at least a part of the cavity piece on the runner gate side with respect to the chip holding piece, and the cavity volume of at least a part of the cavity piece is relative to the chip holding piece pressed against the chip surface. In the position where the cavity is reduced, the mold resin is filled in the cavity recess by the operation of the transfer mechanism, and the cavity volume is moved to the position where the cavity volume is expanded by the resin pressure. The mold mold according to claim 1, wherein when the movement in the direction of expanding the volume is restricted, the cavity piece is relatively moved to the position where the cavity volume is reduced again by a further mold closing operation. In the second mold, the tip holding piece is urged and supported by the first coil spring with respect to the chase, the cavity piece is urged and supported by the second coil spring , and the cavity piece is urged and supported. The mold mold according to claim 1 or 2, wherein when the second coil spring is pushed back against the urging by the resin pressure, the movement is restricted by the stopper and the second coil spring moves relative to the tip holding piece. Claims 1 to 3 claim that the cavity piece moves relative to the height of the lower surface of the chip pressed against the chip holding piece by the mold closing operation, and moves relative to the height position of the upper surface of the chip by the resin pressure. Mold mold described in any of. The mold according to any one of claims 1 to 4, wherein the tip holding pieces are arranged on the tip holding pieces so as to face the chips. The mold according to any one of claims 1 to 5, wherein a reduced pressure space is formed in the mold by the mold closing operation by the first mold and the second mold. The invention according to any one of claims 1 to 6, wherein a film is attracted and held on a clamp surface including the cavity recess of the second mold and is pressed against the chip surface by the chip holding piece via the film. The mold described. The mold according to any one of claims 1 to 7, wherein the clamper is provided with an overflow cavity for accommodating the mold resin overflowing from the cavity recess. A resin molding apparatus provided with the mold according to any one of claims 1 to 8. This is a resin molding method in which the insert is exposed to the workpiece on which the insert is mounted and transfer molding is performed.
The process of closing the mold and clamping the work with the clamper that forms the side of the cavity.
The tip holding piece forming the bottom of the cavity is urged by the first coil spring , placed around the tip holding piece while being pressed against the chip surface, and urged by the second coil spring provided between the chase and the tip holding piece. The process of moving the cavity piece relative to the position where the cavity volume is reduced,
The process of operating the transfer mechanism to pressure-feed the molten mold resin into the cavity,
A step of retreating the cavity piece to a position where the cavity volume is expanded against the urging of the second coil spring by the resin pressure fully filled in the cavity and filling the mold resin.
The mold closing operation of the mold mold is performed while the movement of the cavity piece to the position where the cavity volume is expanded is restricted, and the cavity piece is relatively moved to the position where the cavity volume is reduced by the progress of mold closing in the cavity. The process of pressurizing the resin and pushing it out of the cavity,
A resin molding method comprising. The resin molding method according to claim 10, wherein the cavity piece is relatively moved to a first position which is a height position on the lower surface of the chip and molded.

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