Resin Encapsulation Device and Resin Encapsulation Method

Abstract

Provided are a resin sealing device and a resin sealing method capable of double-sided exposed molding in which, even in molding of relatively large electronic components such as power semiconductors, the end faces of the electronic components are pressed with an appropriate pressing force, and resin burrs are not generated and the electronic components are not damaged. 【Solution means】The resin sealing device includes a resin sealing mold 1 for clamping an electronic component 11 in which a heat sink 17 with exposed end faces laminated on both sides of a substrate 12 is clamped by an upper mold 2 and a lower mold 3 forming a molding cavity 10, and resin-sealing the exposed end faces 17A and 17B of the heat sink 17; a movable core 22 for pressing the electronic component 11 disposed in the molding cavity 10 from the upper mold 2 side toward the lower mold 3 side; a pressure measurement unit 31 for measuring the pressure applied to the lower mold 3 side during resin filling into the molding cavity 10; and a control unit 6 for controlling the pressing force of the movable core 22 according to the pressure measured by the pressure measurement unit 31.

Description

Technical Field

[0001] The present invention relates to a resin sealing device and a resin sealing method for performing double-sided exposed molding of electronic components.

Background Art

[0002] Electronic components such as power semiconductors are resin-sealed and molded with heat dissipation members and the like arranged on both sides of a substrate exposed due to their functional characteristics. However, due to the structure of the electronic components, chips and the like are laminated between the substrate and the heat dissipation member, so the electronic components before resin sealing have variations in thickness for each individual.

[0003] By the way, in order to increase the production efficiency of semiconductors, when performing double-sided exposed molding of a plurality of electronic components at once with one mold, the resin is injected by pressing both end faces of the electronic components on each cavity surface of the upper and lower molds, and resin-sealed and molded. However, due to the variation in thickness for each individual as described above, those with a thinner thickness form a gap between the cavity surface and the end face of the electronic component, allowing the resin to penetrate and generating resin burrs. On the other hand, those with a thicker thickness have a problem that excessive force is applied to both end faces of the electronic component, damaging the electronic component.

[0004] In order to solve such problems, a technique has been disclosed in which the cavity end face for pressing the electronic component is configured with a movable core, and the movable core is pushed by a spring to absorb the variation in thickness (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the method of pushing the movable core with a spring as described above, when clamping the upper and lower molds, since the movable core presses the end face of the electronic component by the spring force, it is necessary to set the spring pressure within a range where the electronic component is not damaged.

[0007] Also, in resin encapsulation molding, after mold clamping, it is necessary to inject and fill the encapsulating resin into the cavity, and completely extrude the air in the cavity so that voids (air bubbles) do not occur in the molded encapsulating resin. Therefore, when injecting the resin, pressure (resin pressure) is applied to the resin (for example, about 6 to 10 MPa), and the air is discharged from the air vent.

[0008] As described above, when the spring pressure is set to a level where the electronic component is not damaged, after mold clamping, when resin is injected and resin pressure is applied, if the resin pressure exceeds the spring pressure, the movable core will be pushed back, creating a gap between the end face of the electronic component and the pressing surface of the movable core, and there is a risk that resin will penetrate into this gap and resin burrs will occur.

[0009] Also, since the resin seals the gaps inside the laminated structure of the electronic component, it also enters the inside of the electronic component. As the movable core is pushed back by the resin pressure, the laminated members of the electronic component are also pushed apart, and there is a risk that the laminated members will peel off.

[0010] Furthermore, in the method described in Patent Document 1, since the pressing force is only the spring pressure, when adjusting the pressing force, replacement work of the spring is required.

[0011] Also, the method described in Patent Document 1 is assumed for relatively small electronic components such as image sensors. However, in the case of relatively large electronic components such as power semiconductors, since the cavity volume is large, a high injection pressure is required to inject the resin in a short time, and a high resin pressure is also required to discharge the voids.

[0012] Therefore, especially when molding relatively large electronic components such as power semiconductors, in addition to the pressing force of the movable core, a high resin pressure is also applied, so an excessive load is likely to be applied to the electronic component, and it is necessary to prevent the electronic component from being damaged.

[0013] Therefore, in the present invention, an object is to provide a resin sealing device and a resin sealing method capable of double-sided exposure molding in which even when molding a relatively large electronic component such as a power semiconductor, the end face of the electronic component is pressed with an appropriate pressing force, and no resin burrs are generated and the electronic component is not damaged.

Means for Solving the Problems

[0014] The resin sealing device of the present invention clamps an electronic component in which an exposure member exposing end faces is laminated on both sides of a substrate by a first mold and a second mold forming a molding cavity, exposes the exposed end faces of the exposure members, and seals with resin. A resin sealing mold, a pressing member for pressing the electronic component disposed in the molding cavity from the first mold side to the second mold side, a pressure measuring unit for measuring the pressure applied to the second mold side during resin filling into the molding cavity, and a control unit for controlling the pressing force of the pressing member according to the pressure measured by the pressure measuring unit.

[0015] According to the resin sealing device of the present invention, the electronic component disposed in the molding cavity is pressed from the first mold side to the second mold side, the pressure applied to the second mold side during resin filling into the molding cavity is measured, and the pressing force of the pressing member is controlled according to the measured pressure. Thus, while preventing an excessive load from being applied to the electronic component during resin injection, no gap is generated in the exposed end face of the electronic component, and resin leakage can be prevented. Further, peeling of the electronic component due to the resin pressure during resin filling can be prevented.

[0016] Preferably, the pressure measuring unit includes a placement portion with which the exposed end face of the exposure member on the second mold side of the electronic component abuts, a pressure detection portion for detecting the pressure applied to the placement portion, and an elastic member for biasing the placement portion toward the first mold side to enable the placement portion and the pressure detection portion to be separated and contacted. Thereby, after separating the placement portion and the pressure detection portion by the elastic member to reset the load applied to the pressure detection portion, the electronic component is clamped by the first mold and the second mold to bring the placement portion into contact with the pressure detection portion, and the pressure actually applied to the electronic component during resin injection can be directly detected.

[0017] It is desirable that there be a plurality of pressure detection units. Thereby, the load applied to the pressure measurement unit can be dispersed and measured by the plurality of pressure detection units.

[0018] The pressing member is preferably a movable core having a pressing surface with substantially the same dimensional shape as the exposed end surface of the exposed member on the first mold side of the electronic component. Thereby, the movable core can press the electronic component in a state of being in close contact with the exposed end surface of the exposed member on the first mold side of the electronic component without any gap, and can prevent resin leakage without generating a gap on the exposed end surface of the electronic component.

[0019] Also, it is desirable that there be a plurality of molding cavities. With the plurality of molding cavities, it becomes possible to resin-seal and mold a plurality of electronic components simultaneously.

[0020] The resin-sealing method of the present invention is a resin-sealing method in which an electronic component in which exposed members exposing end surfaces are laminated on both surfaces of a substrate is clamped by a first mold and a second mold that form a molding cavity, and the exposed end surfaces of the exposed members are exposed and resin-sealed, characterized by pressing the electronic component disposed in the molding cavity from the first mold side toward the second mold side by a pressing member, measuring the pressure applied to the second mold side during resin filling into the molding cavity by a pressure measurement unit, and controlling the pressing force of the pressing member according to the pressure measured by the pressure measurement unit.

[0021] According to the resin-sealing method of the present invention, by pressing the electronic component disposed in the molding cavity from the first mold side toward the second mold side, measuring the pressure applied to the second mold side during resin filling into the molding cavity, and controlling the pressing force of the pressing member according to the measured pressure, it is possible to prevent an excessive load from being applied to the electronic component during resin injection, prevent a gap from occurring in the exposed end surface of the electronic component, and prevent resin leakage. Also, it is possible to prevent peeling of the electronic component due to the resin pressure during resin filling.

[0022] In addition, in the resin sealing method of the present invention, it is desirable to dispose a release film between the pressure measurement unit and the electronic component. Thereby, resin leakage into the gap between the pressure measurement unit and the electronic component can be prevented.

Advantages of the Invention

[0023] According to the present invention, it is possible to perform double-sided exposed molding without generating resin burrs and damaging the electronic components while preventing excessive load from being applied to the electronic components during resin injection.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0025] FIG. 1 is a schematic cross-sectional view showing an enlarged part of the resin sealing mold of the resin sealing device in the embodiment of the present invention, FIG. 2 is a schematic cross-sectional view showing a state where an electronic component is arranged in the resin sealing mold of FIG. 1, FIG. 3 is a schematic cross-sectional view showing a state where an electronic component is clamped in the resin sealing mold of FIG. 1, and FIG. 4 is a schematic cross-sectional view showing a state where resin is injected and pressurized into the resin sealing mold of FIG. 1.

[0026] As shown in FIG. 1, the resin encapsulation device according to the embodiment of the present invention has a resin encapsulation mold 1 that clamps electronic components 11 (see FIG. 2) in a plurality of molding cavities 10 formed by an upper mold 2 as a first mold and a lower mold 3 as a second mold, and performs resin encapsulation. In each figure, only one molding cavity 10 is illustrated, but the resin encapsulation mold 1 forms a plurality of electronic components by double-sided exposed molding at once with a plurality of molding cavities 10.

[0027] The electronic component 11 is, for example, a structure in which a support column 14 is disposed on a chip 13 mounted on a substrate 12, and a heat sink 15, a ceramic plate 16, and a heat sink 17 are laminated in this order on the support column 14. The heat sink 15, the ceramic plate 16, and the heat sink 17 are disposed on both the upper and lower surfaces of the substrate 12. The heat sinks 15 and 17 are, for example, copper plates. The heat sink 17 disposed on the outermost sides of both the upper and lower surfaces of the substrate 12 is an exposed member that exposes the upper and lower end faces, and the surfaces, which are the respective exposed end faces, are exposed and resin-encapsulation molded.

[0028] As shown in FIG. 2, cavity recesses 20 and 30 that constitute the molding cavity 10 are respectively formed on the lower surface of the upper mold 2 and the upper surface of the lower mold 3. Further, at least one of the cavity recesses 20 and 30 of the upper mold 2 and the lower mold 3 is provided with a resin injection port 2A for injecting resin into the molding cavity 10 and an air vent 2B for discharging air in the molding cavity 10. The upper mold 2 and the lower mold 3 are configured to be installed in a press device (not shown) so as to be relatively close to and separated from each other.

[0029] Further, a through hole 21 is provided in the bottom surface (the upper surface in the illustrated example) 20A of the cavity recess 20 of the upper mold 2. The through hole 21 is a hole penetrating from the upper surface 2C of the upper mold 2 to the cavity recess 20. A movable core 22 as a pressing member for pressing the electronic component 11 disposed in the molding cavity 10 from the upper mold 2 side to the lower mold 3 side is inserted into the through hole 21. The movable core 22 is movable in the vertical direction within the through hole 21. The movable core 22 presses the electronic component 11 disposed in the molding cavity 10 by operating within the through hole 21. The movable core 22 has a pressing surface having substantially the same dimensional shape as the surface 17A which is the exposed end surface of the upper heat dissipation plate 17 which is the exposed member on the upper mold 2 side of the electronic component 11.

[0030] On the other hand, a pressure measurement unit 31 is provided in the bottom surface (the lower surface in the illustrated example) 30A of the cavity recess 30 of the lower mold 3. The pressure measurement unit 31 includes a movable core 32 as a mounting portion on which the electronic component 11 is mounted, a pressure sensor 33 as a pressure detection unit for detecting the pressure applied to the movable core 32, and a spring 34 as an elastic member for biasing the movable core 32 toward the upper mold 2 side. The movable core 32 is movable in the vertical direction within a hole 32A formed in the lower mold 3. A plurality of pressure sensors 33 are provided so as to be able to disperse and measure the load applied to the pressure measurement unit 31.

[0031] The surface 17B which is the exposed end surface of the lower heat dissipation plate 17 which is the exposed member on the lower mold 3 side of the electronic component 11 abuts against the surface of the movable core 32. When pressure is applied to the surface 17A of the upper heat dissipation plate 17 on the upper surface of the electronic component 11 by the movable core 22 of the upper mold 2, the surface 17B of the lower heat dissipation plate 17 on the lower surface of the electronic component 11 is pressed against the bottom surface 30A of each cavity recess 30 of the lower mold 3. The spring 34 resets the load due to the clamping of the electronic component 11 in order to directly measure by the pressure sensor 33 the pressure actually applied to the electronic component 11 during resin filling into the molding cavity 10. The spring 34 enables the movable core 32 and the pressure sensor 33 to be separated and contacted. The movable core 32 of the lower mold 3 is pressed toward the upper mold 2 side by the spring 34, and in the state before clamping, the movable core 32 is separated from the pressure sensor 33.

[0032] Further, as shown in FIG. 3, the resin sealing device includes a pressing member 4 that presses the movable core 22, and a pressing mechanism 5 that presses the pressing member 4. The resin sealing device also includes a control unit 6 that controls the pressing mechanism 5 and the like.

[0033] Pressure sensors 7 for detecting the pressing force of the pressing member 4 are respectively provided at the tip of the pressing member 4. The control unit 6 controls the movement amount of the pressing member 4 based on the detection results of the pressure sensors 7 and 33, thereby managing the forces against each electronic component 11 and the resin pressure via the pressing member 4 and the movable core 22.

[0034] Between the pressing member 4 and the movable core 22, a first elastic member 23A and a second elastic member 23B having different spring constants are arranged in parallel as a set of elastic members. As the elastic members 23A and 23B, for example, Belleville springs (disc springs) can be stacked and used. Plates 24 as elastic member pressing plates are respectively provided between the elastic members 23A and 23B and the pressing member 4.

[0035] In the present embodiment, the spring constant of the first elastic member 23A is smaller than that of the second elastic member 23B. Also, as shown in FIG. 3, the thickness of the first elastic member 23A is thicker than that of the second elastic member 23B. Therefore, when the plate 24 is pressed by the pressing member 4, the plate 24 first compresses the first elastic member 23A and then compresses the second elastic member 23B. In the initial position of the movable core 22, the first elastic member 23A may be compressed by a predetermined amount, but the second elastic member 23B is not compressed.

[0036] Next, a resin sealing method using the resin sealing device having the above configuration will be described. As shown in FIG. 1, the upper mold 2 and the lower mold 3 of the resin sealing mold 1 are separated to open the molding cavity 10 (cavity recesses 20 and 30), and the electronic component 11 is supplied and placed on the movable core 32 in the opened cavity recess 30 as shown in FIG. 2. At this time, the movable core 32 is biased toward the upper mold 2 by the spring 34, and the movable core 32 is separated from the pressure sensor 33.

[0037] Thereafter, as shown in FIG. 3, the upper mold 2 and the lower mold 3 are brought closer to clamp the resin sealing mold 1. In this state, the electronic component 11 is fixed in position by being clamped by the resin sealing mold 1 on both the left and right sides of the cavity recesses 20 and 30. At this time, as the spring 34 bends, the movable core 32 comes into contact with the pressure sensor 33. Further, the molding cavity 10 is sealed and becomes a closed state.

[0038] At this time, among the plurality of elastic members 23A and 23B provided between the pressing member 4 and the movable core 22, the elastic member with a small spring constant, that is, the first elastic member 23A bends first, absorbs the difference in thickness between the plurality of electronic components 11 in the plurality of molding cavities 10, and presses the electronic component 11 corresponding to each first elastic member 23A with a small compressive force. The load applied to the electronic component 11 can be measured by the pressure sensor 33. The electronic component 11 is not pressed by the second elastic member 23B with a large spring constant, and the electronic component 11 is not damaged by an excessive force.

[0039] Next, the control unit 6 controls the pressing mechanism 5 to press the plate 24 with the pressing member 4. Then, as shown in FIG. 4, when the resin 9 is injected and filled into the molding cavity 10 from the resin injection port 2A, respectively, the resin pressure in the molding cavity 10 rises. Along with this rise in resin pressure, when the control unit 6 controls the pressing mechanism 5 so that each movable core 22 is not pushed back and presses with each pressing member 4, the second elastic member 23B having a large spring constant is compressed following the first elastic member 23A having a small spring constant. As a result, the total compression force of these elastic members 23A and 23B acts on the movable core 22 to generate a force corresponding to the resin pressure, so that no gap is generated between the movable core 22 and the end face of the electronic component 11 (the surface 17A of the upper heat sink 17), and resin leakage can be prevented. Further, peeling of the electronic component 11 due to the resin pressure during resin filling can be prevented.

[0040] That is, according to the resin sealing mold 1 and the resin sealing device including the same in the present embodiment, even if there is a difference in thickness between the electronic components 11, the end faces of the electronic components 11 are pressed with an appropriate pressing force, and there is no generation of resin burrs over all the electronic components 11, and double-sided exposed molding without breakage of the electronic components is possible.

[0041] Further, in the resin sealing device in the present embodiment, the pressing member 4 is provided with the pressure sensor 7, and the pressing force measured by the pressure sensor 7 is fed back to the control unit 6 to control the pressing force of the pressing member 4 by the pressing mechanism 5. Therefore, resin leakage and member breakage can be prevented with a highly accurate and stable pressing force, and the molding quality can be improved. Further, in the resin sealing device in the present embodiment, the pressure applied to the electronic component 11 is directly detected by the pressure sensor 33, and the control unit 6 controls the pressing force of the pressing member 4 by the pressing mechanism 5 according to the resin pressure detected by the pressure sensor 33, thereby preventing the movable core 22 from being pushed back by the resin pressure.

[0042] Here, the control by the control unit 6 will be described in detail with reference to FIG. 5. FIG. 5 is a time chart of the control by the control unit 6. As shown in FIG. 5, the load applied to the electronic component 11 is zero from the start of the (A) - type clamping until the first elastic member 23A starts to pressurize the electronic component 11 in (B). Then, as the first elastic member 23A bends, the spring pressure of the first elastic member 23A is applied to the electronic component 11, and after the completion of the (C) - type clamping, resin injection is started.

[0043] (D) During resin filling, when resin pressure is applied, this resin pressure acts in the direction of reducing the pressure on the electronic component 11 (pushing back the movable core 22). Here, the control unit 6 controls the pressing mechanism 5 to press the plate 24 by the pressing member 4 and add the spring pressure of the second elastic member 23B. At this time, the pressure sensor 33 detects the pressure applied to the electronic component 11, that is, the difference between the spring pressures of the first elastic member 23A and the second elastic member 23B and the resin pressure, so the control unit 6 controls the pressing mechanism 5 so that this difference becomes constant.

[0044] (E) After the completion of resin injection, the curing process is started. During the curing process, the pressurizing drive by the pressing mechanism 5 is maintained. (F) After the resin is cured, the curing process is completed, and the decompression drive by the pressing mechanism 5 is started. (G) After the decompression is completed, (H) mold opening is started, (I) the spring pressure of the first elastic member 23A is released, and (J) the mold opening is completed.

[0045] Note that by disposing a release film (not shown) between the end face of the electronic component 11 (the surface 17A of the upper heat sink 17) and the movable core 22, resin leakage into the gap between the through - hole 21 and the movable core 22, the gap between the end face of the electronic component 11 and the pressing surface of the movable core 22, etc. can be prevented. Also, by disposing a release film between the movable core 32 of the lower mold 3 and the other end face of the electronic component 11 (the surface 17B of the lower heat sink 17), resin leakage into the gap between the pressure measurement unit 31 and the other end face of the electronic component 11 can also be prevented.

[0046] In addition, in the resin sealing device according to this embodiment, since the plate 24 is provided between the elastic members 23A and 23B and the pressing member 4, the plate 24 is pressed collectively via the plate 24 without directly pressing the elastic members 23A and 23B having different spring constants. Therefore, stable pressing is possible. Note that the plate 24 can also be omitted.

[0047] The spring loads applied to the movable core 22 by the elastic members 23A and 23B depend on the size of the resin-sealed molded product. As an example, when the electronic component 11 has a large cavity volume such as a power semiconductor and resin injection is performed at a large injection pressure of 12 to 20 MPa, for example, about 15 MPa, the spring load of the first elastic member 23A applied to the movable core 22 is about 4.9 to 6.4 kN (500 to 650 kgf), and the spring load of the second elastic member 23B is about 9.8 to 21.6 kN (1000 to 2200 kgf).

Industrial Applicability

[0048] The resin-sealing mold, resin-sealing device, and resin-sealing method of the present invention are useful as a resin-sealing mold, resin-sealing device, and resin-sealing method for performing double-sided exposed molding of electronic components. In particular, they are suitable for electronic components having a large cavity volume such as power semiconductors and performing resin injection at a large injection pressure of 12 to 20 MPa.

Explanation of Reference Numerals

[0049] 1 Resin-sealing mold 2 Upper mold 2A Resin injection port 2B Air vent 3 Lower mold 4 Pressing member 5 Pressing mechanism 6 Control unit 7 Pressure sensor 9 Resin 10 Molding cavity 11 Electronic component 12 Substrate 13 Chip 14 Support pillar 15, 17 Heat sink 16 ceramic plates 20, 30 cavity recesses 21 through-holes 22 movable cores 23A, 23B elastic members 24 plates 31 pressure measurement parts 32 movable cores 33 pressure sensors 34 springs

Claims

1. a resin sealing die for clamping an electronic component having an exposed member laminated on both sides of a substrate by using a first die and a second die that form a molding cavity, and for exposing the exposed end faces of the exposed member and sealing the electronic component with a resin; a pressing member that presses the electronic component placed in the molding cavity from the first mold side to the second mold side; a pressure measuring unit that measures a pressure applied to the second mold side while the resin is being filled into the molding cavity; a control unit that controls the pressing force of the pressing member in response to the pressure measured by the pressure measuring unit; A resin sealing device comprising:

2. 2. The resin sealing device according to claim 1, wherein the pressure measuring unit has a mounting portion against which an exposed end surface of an exposed member of the electronic component on the second mold side abuts, a pressure detection unit that detects the pressure applied to the mounting portion, and an elastic member that enables the mounting portion and the pressure detection unit to be brought into contact with and separated from each other by biasing the mounting portion toward the first mold side.

3. 3. The resin sealing apparatus according to claim 2, wherein the pressure detection unit is a plurality of pressure detection units.

4. 4. The resin sealing device according to claim 3, wherein the pressing member is a movable core having a pressing surface having substantially the same dimensions and shape as an exposed end surface of the exposed member of the electronic component on the first mold side.

5. The resin sealing device according to claim 1 , wherein the molding cavity is a plurality of cavities.

6. A resin sealing method for clamping an electronic component having an exposed member laminated on both sides of a substrate by using a first mold and a second mold that form a molding cavity, and sealing the electronic component with a resin by exposing the exposed end faces of the exposed member, comprising: pressing the electronic component placed in the molding cavity from the first mold side to the second mold side by a pressing member; measuring a pressure applied to the second mold side while the resin is being filled into the molding cavity by a pressure measuring unit; Controlling the pressing force of the pressing member in response to the pressure measured by the pressure measuring unit. The resin sealing method includes the steps of:

7. The resin sealing method according to claim 6, further comprising disposing a release film between the pressure measuring section and the electronic component.

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