Resin sealing device and resin sealing method

Abstract

The present application provides a resin sealing device and a resin sealing method, which can achieve two-side exposed molding without generation of resin burrs and breakage of an electronic component, even if the electronic component such as a power semiconductor is relatively large, by pressing an end surface of the electronic component with a proper pressing force. The resin sealing device includes: a resin sealing mold for resin sealing with an exposed end surface of a heat sink, which is laminated on both sides of a substrate, of an electronic component held by upper and lower molds forming a molding cavity; a movable core for pressing the electronic component arranged in the molding cavity from the upper mold side to the lower mold side; a pressure measuring portion for measuring a pressure applied to the lower mold side during filling of resin into the molding cavity; and a control portion for controlling the pressing force of the movable core according to the pressure measured by the pressure measuring portion.

Description

Technical Field

[0001] This invention relates to a resin sealing device and a resin sealing method for forming double-sided exposed electronic components. Background Technology

[0002] Electronic components such as power semiconductors are formed by sealing them with resin while exposing heat dissipation components and other elements disposed on both sides of a substrate, according to their functional characteristics. However, in the structure of electronic components, chips and other components are stacked between the substrate and the heat dissipation components, so there are thickness variations for each individual electronic component before resin sealing.

[0003] However, in the case of using a single mold to simultaneously expose and mold multiple electronic components on both sides to improve semiconductor manufacturing efficiency, resin is injected by pressing the two end faces of the electronic components with the cavity surfaces of the upper and lower molds for resin sealing. However, as mentioned above, due to variations in the thickness of each individual component, when the thickness is thin, gaps occur between the cavity surface and the end face of the electronic component, allowing resin to seep in and creating resin burrs. On the other hand, when the thickness is thick, there is a problem of excessive force being applied to the two end faces of the electronic component, causing it to break.

[0004] To solve this problem, the following technology is disclosed: the cavity end face of the pressing electronic component is formed by a movable core, and the movable core is pressed by a spring, thereby absorbing the thickness deviation (for example, see Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-225619 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In the method described above, where a spring is used to press the movable core, the movable core presses the end face of the electronic component with the help of the spring force when the upper and lower molds are closed. Therefore, the spring pressure needs to be set within a range that will not damage the electronic component.

[0010] In addition, in resin sealing molding, after mold closing, sealing resin needs to be injected and filled into the cavity to completely expel the air inside the cavity, so that no voids (air bubbles) are generated in the molded sealing resin. Therefore, during resin injection, pressure (resin pressure) (e.g., about 6~10 MPa) is applied to the resin to expel air from the vent.

[0011] As described above, when the spring pressure is set to a level that prevents damage to the electronic component, if the resin pressure exceeds the spring pressure when resin is injected and resin pressure is applied after mold closing, the movable core is pushed back, creating a gap between the end face of the electronic component and the pressing surface of the movable core. Resin may seep into this gap, resulting in resin burrs.

[0012] In addition, the resin also seals the gaps inside the laminated structure of the electronic component, and thus enters the inside of the electronic component. As the movable core is pushed back by the resin pressure, the laminated components of the electronic component are also pushed apart, and the laminated components may peel off.

[0013] Furthermore, in the method described in Patent Document 1, the pressing force is only the spring pressure, so when adjusting the pressing force, the spring needs to be replaced.

[0014] Furthermore, the method described in Patent Document 1 envisions relatively small electronic components such as image sensors, but in the case of relatively large electronic components such as power semiconductors, the cavity volume is large. Therefore, in order to inject resin in a short time, the injection pressure increases, and high resin pressure is also required to expel voids.

[0015] Therefore, especially when molding large electronic components such as power semiconductors, high resin pressure is applied in addition to the pressing pressure of the movable core, which can easily put excessive load on the electronic components and prevent them from breaking.

[0016] Therefore, the object of the present invention is to provide a resin sealing device and a resin sealing method that, even when forming relatively large electronic components such as power semiconductors, can achieve two-sided exposed forming without resin burrs or damage to the electronic components by pressing the end face of the electronic components with appropriate pressure.

[0017] Solution for solving the problem

[0018] The resin sealing device of the present invention includes: a resin sealing mold for holding electronic components with exposed end faces stacked on both sides of a substrate by means of a first mold and a second mold forming a molding cavity, and for performing resin sealing with the exposed end faces of the exposed components exposed; a pressing member for pressing the electronic components 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 the filling of resin into the molding cavity; and a control unit for controlling the pressing force of the pressing member based on the pressure measured by the pressure measuring unit.

[0019] According to the resin sealing device of the present invention, an electronic component disposed in a molding cavity is pressed from a first mold side to a second mold side. The pressure applied to the second mold side during the filling of resin into the molding cavity is measured, and the pressing force of the pressing member is controlled based on the measured pressure. This prevents excessive load on the electronic component during resin injection and avoids gaps at the exposed end faces of the electronic component, thus preventing resin leakage. Furthermore, it prevents the peeling of the electronic component caused by resin pressure during resin filling.

[0020] Preferably, the pressure measuring unit includes: a mounting portion that abuts against the exposed end face of the exposed member on the second mold side of the electronic component; a pressure detection portion that detects the pressure applied to the mounting portion; and an elastic member that can cause the mounting portion to contact and separate from the pressure detection portion by applying force to the mounting portion towards the first mold side. Thus, after the load applied to the pressure detection portion is reset by separating the mounting portion from the pressure detection portion using the elastic member, the electronic component is clamped by the first mold and the second mold, causing the mounting portion to contact the pressure detection portion, allowing direct detection of the pressure actually applied to the electronic component during resin injection.

[0021] Preferably, there are multiple pressure sensing units. This allows the load applied to the pressure measuring unit to be distributed across multiple pressure sensing units for measurement.

[0022] Preferably, the pressing member is a pressing surface having a shape and size substantially the same as the exposed end face of the exposed member on the first mold side of the electronic component. Thus, the movable core can press the electronic component in a tight, gapless manner against the exposed end face of the exposed member on the first mold side of the electronic component, preventing gaps from forming at the exposed end face of the electronic component and further preventing resin leakage.

[0023] Furthermore, it is preferable to have multiple molding cavities. This allows for the simultaneous resin sealing molding of multiple electronic components using multiple molding cavities.

[0024] The resin sealing method of the present invention utilizes a first mold and a second mold forming a molding cavity to clamp electronic components on both sides of a substrate, on which exposed members with exposed end faces are stacked, and resin sealing is performed with the exposed end faces of the exposed members exposed. The method is characterized in that an electronic component disposed in the molding cavity is pressed from the first mold side to the second mold side using a pressing member, and the pressure applied to the second mold side during the filling of resin into the molding cavity is measured by a pressure measuring unit, and the pressing force of the pressing member is controlled based on the pressure measured by the pressure measuring unit.

[0025] According to the resin sealing method of the present invention, an electronic component disposed in a molding cavity is pressed from a first mold side to a 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 based on the measured pressure. This prevents excessive load on the electronic component during resin injection and avoids gaps at the exposed end faces of the electronic component, thus preventing resin leakage. Furthermore, it prevents peeling of the electronic component caused by resin pressure during resin filling.

[0026] Furthermore, the resin sealing method of the present invention preferably includes a release film disposed between the pressure measuring part and the electronic component. This prevents resin leakage into the gap between the pressure measuring part and the electronic component.

[0027] The effects of the invention

[0028] According to the present invention, it is possible to achieve two-sided exposed molding without applying excessive load to electronic components during resin injection and without producing resin burrs or damage to electronic components. Attached Figure Description

[0029] Figure 1 This is a partially enlarged schematic cross-sectional view of the resin sealing mold of the resin sealing device according to an embodiment of the present invention.

[0030] Figure 2 It means in Figure 1 A schematic cross-sectional view of a resin-sealed mold configured with electronic components.

[0031] Figure 3 It means in Figure 1 A schematic cross-sectional view of the state in which the resin-sealed mold holds the electronic components.

[0032] Figure 4 It means to Figure 1 A schematic cross-sectional view of the resin-sealed mold in which resin is injected and pressurized.

[0033] Figure 5 It is a timing diagram based on the control unit.

[0034] Explanation of reference numerals in the attached figures

[0035] 1. Resin sealing mold; 2. Upper mold; 2A. Resin injection port; 2B. Vent hole; 3. Lower mold; 4. Pressing component; 5. Pressing mechanism; 6. Control unit; 7. Pressure sensor; 9. Resin; 10. Molding cavity; 11. Electronic component; 12. Substrate; 13. Chip; 14. Support; 15. 17. Heat sink; 16. Ceramic plate; 20. 30. Cavity recess; 21. Through hole; 22. Movable core; 23A, 23B. Elastic component; 24. Plate; 31. Pressure measuring unit; 32. Movable core; 33. Pressure sensor; 34. Spring Detailed Implementation

[0036] Figure 1 This is a partially enlarged schematic cross-sectional view of the resin sealing mold of the resin sealing device in an embodiment of the present invention. Figure 2 It means in Figure 1 A schematic cross-sectional view of the resin-sealed mold containing electronic components. Figure 3 It means in Figure 1 A schematic cross-sectional view of the resin-sealed mold clamp holding electronic components. Figure 4 It means in Figure 1 A schematic cross-sectional view of the resin-sealed mold in which resin is injected and pressurized.

[0037] like Figure 1 As shown, the resin sealing device according to an embodiment of the present invention includes a resin sealing mold 1, which holds electronic components 11 (see reference 1) within a plurality of forming cavities 10 formed by an upper mold 2 serving as a first mold and a lower mold 3 serving as a second mold. Figure 2 Resin sealing is performed. In addition, in each figure, only one molding cavity 10 is shown, but the resin sealing mold 1 is a mold that uses multiple molding cavities 10 to expose both sides of multiple electronic components at one time.

[0038] Electronic component 11, for example, has a support 14 disposed on a chip 13 mounted on a substrate 12, on which a heat sink 15, a ceramic plate 16, and a heat sink 17 are sequentially stacked. Furthermore, the heat sink 15, ceramic plate 16, and heat sink 17 are disposed on the upper and lower surfaces of the substrate 12. The heat sinks 15 and 17 are, for example, copper plates. The outermost heat sink 17 disposed on the upper and lower surfaces of the substrate 12 is an exposed member that exposes its upper and lower end faces, and is resin-sealed to expose the surfaces of each exposed end face.

[0039] like Figure 2As shown, cavity recesses 20 and 30 constituting the molding cavity 10 are formed on the lower surface of the upper mold 2 and the upper surface of the lower mold 3, respectively. Furthermore, at least one of the cavity recesses 20 and 30 in the upper mold 2 and the lower mold 3 has a resin injection port 2A for injecting resin into the molding cavity 10 and an exhaust port 2B for discharging air from the molding cavity 10. Additionally, the upper mold 2 and the lower mold 3 are configured to be mounted on a stamping device (not shown) so that they can approach and separate relative to each other.

[0040] Furthermore, a through hole 21 is provided on the bottom surface (upper surface of the cavity recess 20 in the example) 20A of the cavity recess 20 of the upper mold 2. The through hole 21 is a hole that extends from the upper surface 2C of the upper mold 2 to the cavity recess 20. A movable core 22 is inserted into the through hole 21. The movable core 22 serves as a pressing member that presses the electronic component 11 disposed in the molding cavity 10 from the upper mold 2 side to the lower mold 3 side. The movable core 22 is capable of moving in the vertical direction within the through hole 21. By moving within the through hole 21, the movable core 22 presses the electronic component 11 disposed in the molding cavity 10. The movable core 22 has a pressing surface that is approximately the same size and shape as the exposed end face (surface 17A) of the exposed member on the upper mold 2 side of the electronic component 11, i.e., the exposed end face of the heat sink 17 on the upper mold 2 side.

[0041] On the other hand, a pressure measuring unit 31 is provided on the bottom surface (lower surface of the cavity recess 30 in the example) 30A of the cavity recess 30 of the lower mold 3. The pressure measuring unit 31 includes: a movable core 32 serving as a mounting part for the electronic component 11; a pressure sensor 33 serving as a pressure detection part for detecting the pressure applied to the movable core 32; and a spring 34 serving as an elastic member that applies force to the movable core 32 towards the upper mold 2. The movable core 32 is capable of moving in the vertical direction within the hole 32A formed in the lower mold 3. Multiple pressure sensors 33 are provided in such a way that they can measure the load applied to the pressure measuring unit 31 in a distributed manner.

[0042] The exposed end face (surface 17B) of the lower mold 3 side of the electronic component 11, i.e., the exposed end face of the lower heat sink 17, abuts against the surface of the movable core 32. When pressure is applied to the surface 17A of the upper heat sink 17 of the electronic component 11 by the movable core 22 of the upper mold 2, the surface 17B of the lower heat sink 17 of the electronic component 11 is pressed against the bottom surface 30A of each cavity recess 30 of the lower mold 3. In order to directly measure the pressure actually applied to the electronic component 11 during the filling of resin into the molding cavity 10 by the pressure sensor 33, the spring 34 resets the load generated by clamping on the electronic component 11. The spring 34 can make the movable core 32 contact and separate from the pressure sensor 33. The movable core 32 of the lower mold 3 is pressed to 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.

[0043] In addition, such as Figure 3 As shown, the resin sealing device includes a pressing member 4 for pressing the movable core 22 and a pressing mechanism 5 for pressing the pressing member 4. Additionally, the resin sealing device includes a control unit 6 for controlling the pressing mechanism 5, etc.

[0044] Pressure sensors 7 are provided at the front end of the pressing member 4 to detect the pressing force of the pressing member 4. The control unit 6 controls the amount of movement of the pressing member 4 based on the detection results of each pressure sensor 7, 33, thereby managing the force against the pressure of each electronic component 11 and the resin via the pressing member 4 and the movable core 22.

[0045] Between the pressing member 4 and the movable core 22, a first elastic member 23A and a second elastic member 23B with different spring constants are arranged side by side as a group of elastic members. For example, Belleville springs (disc springs) can be used overlappingly as elastic members 23A and 23B. A plate 24, serving as an elastic member pressing plate, is provided between the elastic members 23A and 23B and the pressing member 4.

[0046] In this embodiment, the spring constant of the first elastic member 23A is smaller than the spring constant of the second elastic member 23B. Additionally, as... Figure 3 As shown, the thickness of the first elastic member 23A is greater 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 addition, at the initial position of the movable core 22, the first elastic member 23A can also be compressed by a predetermined amount, but the second elastic member 23B is not compressed.

[0047] Next, the resin sealing method of the resin sealing device with the above structure will be described.

[0048] like Figure 1 As shown, the upper mold 2 and lower mold 3 of the resin sealing mold 1 are separated, thus opening the molding cavity 10 (cavity recess 20, cavity recess 30), as shown. Figure 2 As shown, electronic components 11 are supplied to and mounted on the movable core 32 within the open cavity recess 30. At this time, the movable core 32 is subjected to force by the spring 34 towards the upper mold 2, and the movable core 32 separates from the pressure sensor 33.

[0049] Then, as Figure 3 As shown, the upper mold 2 and lower mold 3 are brought close together to close the resin sealing mold 1. In this state, the electronic component 11 is held in place by the resin sealing mold 1 on the left and right sides of the cavity recesses 20 and 30. At this time, the movable core 32 comes into contact with the pressure sensor 33 by the deflection of the spring 34. In addition, the molding cavity 10 is sealed and becomes closed.

[0050] At this time, the elastic member with the smaller spring constant, namely the first elastic member 23A, is deflected first among the multiple elastic members 23A and 23B respectively provided between the pressing member 4 and the movable core 22. This deflection absorbs the thickness difference between the multiple electronic components 11 within the multiple forming cavities 10, and presses the electronic component 11 corresponding to each of the first elastic members 23A with a smaller compressive force. The load applied to the electronic component 11 can be measured by the pressure sensor 33. The electronic component 11 will not be pressed by the second elastic member 23B with a larger spring constant, and the electronic component 11 will not be damaged due to excessive force.

[0051] Next, the pressing mechanism 5 is controlled by the control unit 6, and the pressing member 4 presses the plate 24. Afterwards, as... Figure 4 As shown, when filling resin 9 is injected into the molding cavity 10 through resin injection port 2A, the resin pressure inside the molding cavity 10 increases. As this resin pressure increases, if the pressing mechanism 5 is controlled by the control unit 6 and pressed by the pressing members 4 in a manner that prevents the movable core 22 from being pushed back, then the first elastic member 23A with a smaller spring constant and the second elastic member 23B with a larger spring constant are compressed. Thus, the combined compressive force of these elastic members 23A and 23B is applied to the movable core 22, generating a force corresponding to the resin pressure. Therefore, 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), preventing resin leakage. Furthermore, it prevents the electronic component 11 from peeling off due to the resin pressure during resin filling.

[0052] That is, according to the resin sealing mold 1 and the resin sealing device equipped with the resin sealing mold 1 in this embodiment, even if there is a thickness difference between the electronic components 11, the end face of the electronic components 11 can be pressed with appropriate pressing pressure, thereby achieving two-sided exposed forming without resin burrs on the entire electronic component 11 and without damage to the electronic component.

[0053] Furthermore, in the resin sealing device of this embodiment, the pressing member 4 is equipped with a pressure sensor 7. The pressing force measured by the pressure sensor 7 is fed back to the control unit 6, and the pressing mechanism 5 controls the pressing force of the pressing member 4. Therefore, resin leakage and component damage can be prevented with a high-precision and stable pressing force, thereby improving molding quality. In addition, in the resin sealing device of this embodiment, the pressure applied to the electronic component 11 is directly detected by the pressure sensor 33. The control unit 6 controls the pressing force of the pressing mechanism 5 on the pressing member 4 based on the resin pressure detected by the pressure sensor 33, thereby preventing the movable core 22 from being pushed back by the resin pressure.

[0054] Here, refer to Figure 5 Detailed explanation of control based on control unit 6. Figure 5 This is a timing diagram based on the control unit 6. For example... Figure 5 As shown, from (A) when the mold is closed until (B) when the first elastic member 23A begins to pressurize the electronic component 11, the load applied to the electronic component 11 is zero. Furthermore, as the first elastic member 23A flexes, the spring pressure of the first elastic member 23A is applied to the electronic component 11, and (C) after the mold is closed, resin injection begins.

[0055] (D) During resin filling, if resin pressure is applied, this resin pressure acts in the direction of depressurizing the pressure applied to the electronic component 11 (pushing the movable core 22 back). Here, the pressing mechanism 5 is controlled by the control unit 6, and the pressing plate 24 is pressed by the pressing member 4, applying 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, i.e., the difference between the spring pressure of the first elastic member 23A and the second elastic member 23B and the resin pressure, and therefore the pressing mechanism 5 is controlled by the control unit 6 to keep this difference constant.

[0056] (E) After the resin injection is completed, the curing process begins. During the curing process, the pressing mechanism 5 is kept pressurized. (F) After the resin has cured, the curing process is completed, and the pressing mechanism 5 is depressurized. (G) After the depressurization is completed, (H) the mold opening begins, (I) the spring pressure of the first elastic member 23A is released, and (J) the mold opening ends.

[0057] Furthermore, by providing a release film (not shown) between the end face of the electronic component 11 (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, and the gap between the end face of the electronic component 11 and the pressing surface of the movable core 22, can be prevented. Additionally, by also providing a release film between the movable core 32 of the lower mold 3 and the other end face of the electronic component 11 (surface 17B of the lower heat sink 17), resin leakage into the gap between the pressure measuring section 31 and the other end face of the electronic component 11 can also be prevented.

[0058] Furthermore, in the resin sealing device of this embodiment, since a plate 24 is provided between the elastic members 23A and 23B and the pressing member 4, the elastic members 23A and 23B with different spring constants are not pressed directly, but are pressed together through the plate 24. Therefore, stable pressing can be achieved. Alternatively, the plate 24 can be omitted.

[0059] The spring load applied to the movable core 22 by the elastic members 23A and 23B depends on the size of the resin-sealed molded part. However, as an example, when the electronic component 11 is a power semiconductor or other component with a large cavity volume and resin injection using a large injection pressure of 12 MPa to 20 MPa, for example, about 15 MPa, the spring load applied to the movable core 22 by the first elastic member 23A is about 4.9 kN to 6.4 kN (500 kgf to 650 kgf), and the spring load of the second elastic member 23B is about 9.8 kN to 21.6 kN (1000 kgf to 2200 kgf).

[0060] Industrial availability

[0061] The resin sealing mold, resin sealing device, and resin sealing method of the present invention are useful as resin sealing molds, resin sealing devices, and resin sealing methods for forming electronic components with both sides exposed, and are particularly suitable for electronic components such as power semiconductors with large cavity volumes and resin injection using a large injection pressure of 12 to 20 MPa.

Claims

1. A resin sealing device, wherein, The resin sealing device includes: A resin sealing mold is used to perform resin sealing on electronic components on both sides of a substrate, which are stacked with exposed members that expose their end faces, by using a first mold and a second mold that form a molding cavity to clamp the exposed end faces of the exposed members. The pressing member presses the electronic components disposed in the forming cavity from the first mold side to the second mold side; A pressure measuring unit measures the pressure applied to the second mold side during the filling of resin into the molding cavity; and The control unit controls the pressing force of the pressing member based on the pressure measured by the pressure measuring unit.

2. The resin sealing device according to claim 1, wherein, The pressure measuring unit has a mounting portion that abuts against the exposed end face of the exposed member on the second mold side of the electronic component; A pressure detection unit that detects the pressure applied to the mounting portion; And an elastic member, which can make the mounting part contact and separate from the pressure detection part by applying force to the mounting part toward the first mold side.

3. The resin sealing device according to claim 2, wherein, There are multiple pressure detection units.

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

5. The resin sealing device according to any one of claims 1 to 4, wherein, The forming cavity is multiple.

6. A resin sealing method comprising using a first mold and a second mold forming a molding cavity to clamp electronic components having exposed end faces stacked on both sides of a substrate, wherein resin sealing is performed with the exposed end faces of the exposed components exposed, wherein, The resin sealing method includes: The electronic components disposed in the forming cavity are pressed from the first mold side to the second mold side using a pressing member; The pressure applied to the second mold side during the filling of the molding cavity with resin is measured using a pressure measuring unit; and The pressing force of the pressing member is controlled based on the pressure measured by the pressure measuring unit.

7. The resin sealing method according to claim 6, wherein, The resin sealing method includes: placing a release film between the pressure measuring part and the electronic component.

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