JP6907044B2 - Resin molding device and resin molding method - Google Patents

Description

The present invention relates to a resin molding apparatus for performing transfer molding.

Conventionally, a resin molding device for performing transfer molding has been known. When performing transfer molding, a resin tablet is placed on each of a plurality of plungers corresponding to a plurality of cals, and each plunger is raised to press each resin tablet. As a result, the resin is filled in the cavity formed by the mold of the resin molding device.

By the way, the weight of each resin tablet arranged on each plunger varies, and in order to manufacture a high-quality resin molded product, it is necessary to absorb the variation in the weight of each resin tablet.

For example, in Patent Document 1, in order to absorb variations in the weight of each resin tablet, a resin mold that performs transfer molding while controlling the resin molding pressure by using a spring (equal pressure mechanism) that applies a force in the upward direction of each plunger. The device is disclosed.

Further, in recent years, SiP (System in Package) may include not only semiconductor ICs but also components that cannot withstand high resin molding pressures (for example, 5 to 10 MPa) such as passive elements such as Saw devices. There is a need for a resin molding apparatus capable of performing transfer molding with a low resin molding pressure (for example, 1 to 3 MPa or less).

JP-A-2009-107197

The resin molding apparatus disclosed in Patent Document 1 uses a spring so that the resin molding pressure at the time of transfer molding becomes uniform. However, in the resin molding apparatus of Patent Document 1, since the spring is affected by noise, the relationship between the transfer drive amount and the pressure cannot be accurately measured when a low resin molding pressure (pressure) is applied. Therefore, in the resin molding apparatus of Patent Document 1, it is difficult to perform accurate transfer molding with a low resin molding pressure.

Therefore, an object of the present invention is to provide a resin molding apparatus and a resin molding method capable of accurate transfer molding with a low resin molding pressure.

The resin molding device as one aspect of the present invention is in a state where the first mold in which the cavity is formed, the second mold, the first mold, and the second mold are clamped. A plurality of plungers for filling the inside of the cavity with resin, a multi-transfer unit for moving the plurality of plungers for filling the resin, and a multi-transfer unit provided in the first mold and inside the cavity. The multi-transfer unit has a first pressure sensor that directly measures pressure and a control unit that controls the operation of the multi-transfer unit, and the multi-transfer unit has a plurality of fixed units that fix and hold each of the plurality of plungers. In the first mold, a common cal is formed for the plurality of plungers, and the cal is a plurality of cal portions corresponding to each of the plurality of plungers and the plurality of cal portions. The resin is melted by moving the plurality of plungers in a state where the first mold and the second mold are clamped by the connecting portion for connecting the cal portion. The inside of the cavity is filled through the runner portion and the gate portion, and the control unit controls the operation of the multi-transfer unit based on the measured value of the first pressure sensor.

The resin molding method as another aspect of the present invention includes a step of directly measuring the pressure inside the cavity using a first pressure sensor provided in the first mold having the cavity, and a plurality of plungers. Using the second pressure sensor provided in the multi-transfer unit for moving the device, the step of measuring the load applied to the second pressure sensor, the measured value by the first pressure sensor, and the second Based on the value measured by the pressure sensor, the step of feedback-controlling the load applied to the second pressure sensor and the resin molding are performed by applying the load to the second pressure sensor and moving the plunger. The first mold has a step, and a common cal is formed for the plurality of plungers, and the cal has a plurality of cal portions corresponding to each of the plurality of plungers. By providing a connecting portion for connecting the plurality of cal portions and moving the plurality of plungers in a state where the first mold and the second mold are clamped in the step of performing the resin molding. the cull molten tree fat is filled in the cavity through the runner portion and a gate portion.

Other objects and effects of the present invention will be described in the following embodiments.

According to the present invention, it is possible to provide a resin molding apparatus and a resin molding method capable of accurate transfer molding with a low resin molding pressure.

It is an overall block diagram of the resin molding apparatus in this embodiment. It is sectional drawing of the resin molding apparatus in this embodiment (before resin molding). It is sectional drawing of the resin molding apparatus in this embodiment (after resin molding). It is a figure which shows the relationship of the transfer position, the transfer pressure, and the cavity pressure in this embodiment. It is a flowchart which shows the resin molding method in this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the resin molding apparatus according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an overall configuration diagram of the resin molding device 100. FIG. 2A is a cross-sectional view of the resin molding apparatus 100 cut along the line AA of FIG. 1 (before resin molding). FIG. 2B is a cross-sectional view of a main part of the resin molding device. FIG. 3A is a cross-sectional view of the resin molding device 100 after resin molding. FIG. 3B is a cross-sectional view of the resin molding apparatus 100 cut along the line BB in FIG. 3A. As shown in FIGS. 1 to 3, the resin molding apparatus 100 of the present embodiment performs resin molding (resin sealing) of the electronic device 31 by transfer molding (transfer molding).

Reference numeral 30 is a substrate. 31 is an electronic device. The electronic device 31 includes a semiconductor chip 32 and a passive element 33, and is usually configured to include a passive element 33 mounted on a mounting substrate separately from the package. The passive element 33 includes an electronic circuit configured in the semiconductor chip 32 to form an electronic circuit, and can be, for example, a filter or a capacitor. Since such a passive element (electronic component) is composed of a material that is softer than a member composed of a silicon substrate such as a semiconductor chip 32, it cannot withstand a high resin pressure and is made of resin. It may be deformed by pressure and its performance may be deteriorated or damaged. As such a passive element (electronic component), a filter is assumed as an example, and more specifically, a Saw filter is assumed, but the present invention is not limited to this. Further, as the capacitor, the same configuration is assumed when an aluminum monolithic capacitor, an electrolytic capacitor, or the like is used. The electronic device 31 may be a semiconductor device including a semiconductor chip 32, and the present embodiment can also be applied to a resin mold of a large electronic device such as an electronic control unit (ECU) for controlling a vehicle. ..

In the resin molding apparatus 100, reference numeral 11 denotes an upper mold as a first mold for determining the shape of the resin to be filled in the electronic device 31 provided on the substrate 30. The upper mold 11 is formed with a cavity 13 for determining the outer shape of the resin package that seals the electronic device 31. The upper mold 11 presses the substrate 30 from the upper surface side at the time of resin molding.

Reference numeral 12 denotes a lower mold as a second mold. A substrate 30 on which the electronic device 31 is mounted is placed on the lower mold 12. The lower mold 12 presses the substrate 30 from the lower surface side at the time of resin molding.

The mold mold of this embodiment (hereinafter, also simply referred to as “mold”) is mainly composed of an upper mold 11 and a lower mold 12. At the time of resin molding, the substrate 30 is clamped (sandwiched) between the upper mold 11 and the lower mold 12, and the cavity 13 formed between the upper mold 11 and the lower mold 12 is filled to fill the electronic device 31. Perform resin molding.

Reference numeral 70 denotes a resin tablet obtained by molding a thermosetting resin or the like into a tablet (cylinder) shape. At the time of resin molding, the resin tablet 70 is put into the pot 18 of the preheated lower mold 12 to be melted, and the plunger 17 is moved upward to pump the molten resin 71 to pump the upper mold 11 and the lower mold. The space between the mold 12 and the mold 12 is filled with the resin 71. The plunger 17 is configured to be slidable up and down along the pot 18 by the transfer mechanism 19.

In this embodiment, instead of the resin tablet 70, the granular resin can be put into the pot 18, or the liquid thermosetting resin can be supplied to the pot by a dispenser (not shown). Further, after covering the parting surfaces of the upper mold 11 and the lower mold 12 with a release film (not shown), the resin 71 is supplied, and the substrate 30 is formed by the upper mold 11 and the lower mold 12 via the release film. Can also be clamped.

By pumping the resin 71 by the plunger 17, the molten resin 71 is supplied to the cavity 13 via the cal 16, the runner 15, and the gate 14. That is, the resin 71 is sequentially supplied to the inside of the cavity 13 from the side near the gate 14 to the side far from the gate 14 (toward the overflow cavity 21).

The resin 71 in which the resin tablet 70 is melted in this way is injected into the space (cavity 13, gate 14, runner 15, cal 16) formed by the upper mold 11 and the lower mold 12. As a result, as shown in FIGS. 3A and 3B, the space (cavity 13, gate 14, runner 15, cal 16) between the upper mold 11 and the lower mold 12 is formed by the resin 71. It will be in a filled state.

The transfer mechanism 19 of the present embodiment is a multi-transfer unit as shown in FIGS. 2 (a) and 3 (b). With such a configuration, the transfer mechanism 19 can slide the plurality of plungers 17a to 17f up and down along each of the plurality of pots 18a to 18f.

In the transfer mechanism 19 of the present embodiment, instead of providing a spring (equal pressure mechanism) for pressing each plunger upward at each lower portion of each of the plurality of plungers 17a to 17f, each of the plurality of plungers 17a to 17f is provided. It is provided with a plurality of rigid portions (fixed portions) 19a to 19f for fixing and holding.

When the transfer molding is repeated, as shown in FIG. 2B, the resin adheres between the plunger 17 and the pot 18 (the inner peripheral surface of the pot 18) and remains as the resin residue 72. .. In this case, if a spring is provided to equalize the pressure pressing the plunger 17, the spring expands and contracts by receiving the force from the plunger 17, so that the movement of the plunger 17 is vertical regardless of the operation by the transfer mechanism 19. An operation of ascending and descending in a direction (vertical direction) will occur. As a result, the sliding friction received by the plunger 17 in the pot 18 is affected by the presence of the residual resin residue 72, and the operation of the plunger 17 becomes unstable in the length direction of the pot 18. On the other hand, according to the present embodiment, since the rigid portion 19 is used instead of the spring, the spring does not expand or contract according to the change in the sliding resistance due to the influence of the resin residue 72, and thus is affected by this. The operation of the plunger 17 is stable without any problem.

By the way, assuming that the cal 16 is provided separately (independently) with respect to each of the plurality of plungers 17a to 17f, the weight variation of the resin tablets 70a to 70f arranged on each of the plungers 17a to 17f. The variation in resin molding pressure due to the above cannot be absorbed by the transfer mechanism side.

Therefore, in the present embodiment, the cal 16 corresponding to each of the plurality of plungers 17a to 17f is integrally configured without being separated. That is, in the upper mold 11, a common cal 16 connected to a plurality of plungers 17a to 17f is formed. As shown in FIG. 2A, a connecting portion 16a is formed in the upper mold 11 of the present embodiment, and a cal portion 16a corresponding to the left cal 16 (plunger 17a to 17c and resin tablets 70a to 70c) is formed. 16b) and the right cal 16 (plunger 17d to 17f and the cal portion 16c corresponding to the resin tablets 70d to 70f) are connected to form an integral structure. However, this embodiment is not limited to this. For example, it is not necessary that all the cals are integrated, and at least two cals corresponding to a plurality of plungers may be integrated so that the amount of resin can be adjusted.

The resin molding apparatus 100 of the present embodiment measures the load (thrust) generated during resin molding in order to control the injection pressure (resin molding pressure) of the resin 71 during transfer molding, and controls the pressure of the transfer mechanism 19. Is done. Therefore, a pressure sensor 20 (second pressure sensor) for measuring the load applied to the transfer mechanism 19 at the time of resin molding is provided below the transfer mechanism 19. Further, in the present embodiment, in order to perform accurate transfer molding even at a low resin molding pressure, the upper mold 11 has a pressure sensor 41 that measures the resin molding pressure (cavity pressure) of the resin 71 filled in the cavity 13. 42 (first pressure sensor) is provided. The pressure sensors 41 and 42 measure the pressure in the cavity 13 in the upward direction, respectively. The pressure sensors 20, 41, and 42 are configured so that the resistor expands and contracts in proportion to the expansion and contraction of the object to be measured and the resistance value changes, and the load cell (strain sensor) that measures the amount of strain using this resistance change. Is.

As shown in FIG. 1, the resin molding device 100 of the present embodiment includes a control unit 50. The control unit 50 controls the operation of the transfer mechanism 19 by controlling the load applied to the transfer mechanism 19 via the pressure sensor 20 by feedback control. When a load is applied to the pressure sensor 20, strain is generated in the pressure sensor 20, and the output voltage of the pressure sensor 20 changes. Therefore, the control unit 50 can calculate the amount of strain based on the change value of the output voltage of the pressure sensor 20, the gauge ratio of the pressure sensor 20, and the input voltage of the pressure sensor 20. Further, it is possible to calculate the pressure (transfer pressure) applied to the pressure sensor 20 from this strain amount and Young's modulus.

Further, in the present embodiment, the control unit 50 calculates the resin molding pressure (cavity pressure) in the cavity 13 based on the signals output from the pressure sensors 41 and 42 provided in the upper mold 11. Then, the control unit 50 performs feedback control so as to apply an appropriate load to the pressure sensor 20 and move the plunger 17 upward based on the respective signals from the pressure sensors 20, 41, and 42. As described above, in the resin molding device 100 of the present embodiment, not only the pressure sensor 20 is provided below the transfer mechanism 19, but also the pressure sensors 41 and 42 that directly measure the resin molding pressure inside the cavity 13 are placed on the upper mold 11. It is provided in.

As a result, the control unit 50 can calculate the resin molding pressure from the more direct cavity pressure instead of the indirect transfer pressure. With such a configuration, according to the resin molding apparatus 100 of the present embodiment, it is possible to accurately measure and control a low resin molding pressure. In the present embodiment, the pressure sensor 41 is preferably arranged near the gate 14 in the cavity outside the molding region of the product, and the pressure sensor 42 is located at a position away from the gate 14 (air vent where air is discharged). Alternatively, it is arranged in the vicinity of the overflow cavity 21). As a result, the cavity pressure from immediately after the start of the resin mold to immediately before the end of the resin mold can be measured more accurately. However, in the present embodiment, two pressure sensors 41 and 42 for detecting the cavity pressure are provided, but the number of pressure sensors is not limited, and for example, only one pressure sensor may be provided. ..

FIG. 4 shows the relationship between the transfer position (the vertical position of the transfer mechanism 19), the transfer pressure (value detected by the pressure sensor 20), and the cavity pressure (value detected by the pressure sensors 41 and 42) in the present embodiment. It is a figure. In FIG. 4A, the vertical axis represents the transfer position and the horizontal axis represents the elapsed time. In FIG. 4B, the vertical axis represents the transfer pressure (solid line) and the cavity pressure (broken line), and the horizontal axis represents the elapsed time. In FIG. 4A, the period in which the transfer position is constant after a predetermined elapsed time has elapsed since the transfer position started to rise is the curing time (cure time) after the resin is filled in the cavity 13. .. As shown in FIG. 4B, as the transfer mechanism 19 moves upward, the transfer pressure and the cavity pressure increase. Also, the cavity pressure is smaller than the transfer pressure.

Next, the resin molding method in the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing a resin molding method. Each step of FIG. 5 is executed by the control unit 50 of the resin molding device 100.

First, in step S101, the control unit 50 acquires the measured value (transfer position) of the pressure sensor 20. Subsequently, in step S102, the control unit 50 acquires the measured value (cavity pressure in the vicinity of the gate 14) of the pressure sensor 41. Subsequently, in step S103, the control unit 50 acquires the measured value of the pressure sensor 41 (cavity pressure in the vicinity of the overflow cavity 21). The order of steps S101 to S103 may be changed, or at least a part of steps S101 to S103 may be performed at the same time. When the number of pressure sensors for measuring the cavity pressure is 3 or more, the number of steps similar to steps S102 and S103 increases according to the number of the pressure sensors. Further, when there is only one pressure sensor for measuring the cavity pressure, one of steps S102 and S103 is omitted.

Subsequently, in step S104, the control unit 50 determines the load to be applied to the transfer mechanism 19 via the pressure sensor 20 based on the measured values of the pressure sensors 20, 41, and 42. Then, the control unit 50 applies the determined load to the transfer mechanism 19, and controls the position of the transfer mechanism 19, that is, the plunger 17 in the vertical direction.

In step S104, for example, the control unit 50 compares the two measured values of the pressure sensors 41 and 42, selects the larger value (maximum value) of the two measured values, and transfers based on the maximum value. The load applied to the mechanism 19 is determined. However, the present embodiment is not limited to this, and the load may be determined based on the average value of the two measured values or one measured value determined according to a predetermined condition such as an elapsed time. good.

Further, in the present embodiment, the control unit 50 is at the same type position, for example, when at least one of the measured values of the pressure sensors 41 and 42 (or the average value of the two measured values, or when a plurality of the pressure sensors 41 and 42 are provided. When (the average value of the measured values) is larger than a predetermined threshold value, the load applied to the transfer mechanism 19 is reduced. As the predetermined threshold value, for example, a value corresponding to the maximum resin molding pressure (or a predetermined pressure smaller than the maximum resin molding pressure) allowed by the electronic device 31 is set, and is appropriately changed according to the type of the electronic device 31. It is possible. With such a configuration, according to the present embodiment, the resin molding pressure (cavity pressure) inside the cavity 13 can be accurately measured, so that the pressure inside the cavity 13 is sure to be larger than the intended pressure. It is possible to prevent it.

Further, in the present embodiment, the control unit 50 is used in combination with, for example, a timer for measuring the drive time of the transfer mechanism 19, so that the measured values of the pressure sensors 41 and 42 (or a plurality of pressure sensors 41 and 42 are each. When it is provided, the time at the time when it rises to a predetermined value (when it reaches a predetermined value) is calculated for at least one of (the average value of the measured values at the same type of position), and the filling is performed based on the slow speed with respect to the scheduled predetermined timing. It is also possible to calculate the state and control the operation. Specifically, when the timing at which the measured values of the pressure sensors 41 and 42 rise to the predetermined values is later than planned, the resin filling is delayed and the maximum resin molding pressure is lowered, so that the load applied to the transfer mechanism 19 is increased. be able to. For example, when the curve of the cavity pressure shown by the broken line in FIG. 3B moves to the right side or when the inclination becomes gentle, a delay occurs, and the above-mentioned operation can be performed.

As described above, in the present embodiment, the transfer mechanism 19 has a plurality of rigid portions 19a to 19f that fix and hold each of the plurality of plungers 17a to 17f. That is, the transfer mechanism 19 does not utilize a spring that elastically holds the plurality of plungers. Further, in the present embodiment, the upper mold 11 is formed with a common cal 16 for the plurality of plungers 17a to 17f, and the upper mold 11 and the lower mold 12 are clamped to the plurality of plungers. As the 17a to 17f move, the resin 71 is filled inside the cavity 13 via the cal 16. At this time, the control unit 50 controls the operation of the transfer mechanism 19 based on the measured values of the pressure sensors 41 and 42. Therefore, according to the present embodiment, it is possible to provide a resin molding apparatus and a resin molding method capable of accurate transfer molding with a low resin molding pressure.

The embodiments of the present invention have been specifically described above. However, the present invention is not limited to the matters described in the above-described embodiment, and can be appropriately modified without departing from the technical idea of the present invention.

11 Upper mold 12 Lower mold 13 Cavity 14 Gate 15 Runner 16 Cal 16a Connecting part 17 Plunger 18 Pot 19 Transfer mechanism (multi-transfer unit)
20 Pressure sensor 21 Overflow cavity 30 Substrate 31 Electronic device 32 Semiconductor chip 33 Passive element 41, 42 Pressure sensor 50 Control unit 70 Resin tablet 100 Resin molding device

Claims (4)

The first mold in which the cavity was formed and
The second mold and
A plurality of plungers for filling the inside of the cavity with the resin in a state where the first mold and the second mold are clamped, and
A multi-transfer unit that moves the plurality of plungers to fill the resin, and
A first pressure sensor provided in the first mold and directly measuring the pressure inside the cavity, and
It has a control unit that controls the operation of the multi-transfer unit.
The multi-transfer unit has a plurality of fixing portions for fixing and holding each of the plurality of plungers.
In the first mold, a common cal is formed for the plurality of plungers.
The cal includes a plurality of cal portions corresponding to each of the plurality of plungers, and a connecting portion for connecting the plurality of cal portions.
By moving the plurality of plungers in a state where the first mold and the second mold are clamped, the molten resin is filled inside the cavity via the cal, runner, and gate. Being done
The control unit is a resin molding device characterized in that the operation of the multi-transfer unit is controlled based on the measured value of the first pressure sensor. It further has a second pressure sensor that measures the load applied to the multi-transfer unit.
The control unit is characterized in that it performs feedback control of the load applied to the multi-transfer unit based on the measured value of the first pressure sensor and the measured value of the second pressure sensor. The resin molding apparatus according to 1. The first pressure sensor includes a plurality of sensors arranged at different positions in the first mold.
The resin molding apparatus according to claim 1 or 2, wherein the control unit selects a maximum value from the measured values of the plurality of sensors and controls the multi-transfer unit using the maximum value. A step of directly measuring the pressure inside the cavity using a first pressure sensor provided in the first mold having the cavity, and
A step of measuring the load applied to the second pressure sensor using a second pressure sensor provided in the multi-transfer unit for moving a plurality of plungers, and a step of measuring the load applied to the second pressure sensor.
A step of feedback-controlling the load applied to the second pressure sensor based on the value measured by the first pressure sensor and the value measured by the second pressure sensor.
It has a step of performing resin molding by applying the load to the second pressure sensor and moving the plunger.
In the first mold, a common cal is formed for the plurality of plungers.
The cal includes a plurality of cal portions corresponding to each of the plurality of plungers, and a connecting portion for connecting the plurality of cal portions.
In performing the resin molding, by moving the plurality of plungers and said first mold and a second mold whilst clamped, molten tree fat the cull, runners, and the gates A resin molding method characterized in that the inside of the cavity is filled through the cavity.

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