JP3407987B2 - Storage method of resin molding die and resin sealing method of electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for sealing and molding electronic components such as ICs, LSIs, diodes and capacitors mounted on a lead frame with a resin material. How to store molds
Law improvement.

[0002]

2. Description of the Related Art Conventionally, electronic parts have been molded with a resin by a transfer molding method. This method, for example, is usually performed by using a resin molding mold as follows. It has been done.

That is, an upper mold (fixed mold) and a lower mold (movable mold) in a resin molding die are heated to a resin molding temperature by a heating means, and the upper and lower dies are opened. I do. Next, the lead frame on which the electronic components are mounted is supplied and set at a predetermined position on the lower mold surface,
Supply the resin tablet into the lower pot. Next, the lower mold is moved upward to clamp the upper and lower molds. At this time,
The electronic component and the lead frame around it are fitted and set in the upper and lower cavities facing the upper and lower mold surfaces, and the resin tablet in the pot is heated and melted sequentially. Will be Next, when the resin material in the pot is pressurized by a plunger and the molten resin material is injected and filled into the upper and lower cavities through the resin passage portion, the electronic components in the two cavities and the lead frame around the electronic components are formed. Then, it is sealed in a resin-sealed molded body (mold package) molded corresponding to the shapes of the two cavities. Therefore, after the required time required for curing the molten resin material has elapsed, the upper and lower molds are opened, and the resin sealing molded bodies in the upper and lower cavities and the cured resin in the lead frame and the resin passage portion are respectively separated. What is necessary is just to release a mold.

Further, when the upper and lower molds are clamped, a space formed on both mold surfaces, that is, a mold comprising at least the pot, the resin passage, the upper and lower cavities, and the like. Since air containing moisture (e.g., moisture in the atmosphere) remains in the space inside the mold, the remaining air is mixed into the molten resin material and the inside of the resin-sealed molded body and Voids are easily formed outside. Therefore, in order to prevent the above-mentioned voids from occurring, a configuration in which the above-mentioned inner space of the mold and the vacuum mechanism (pressure reducing mechanism) are connected to each other is adopted. The vacuum mechanism forcibly sucks and discharges air and the like remaining in the mold space, sets the inside of the mold space to a predetermined degree of vacuum, and further fits into the upper and lower cavities. 2. Description of the Related Art An electronic component on a mounted lead frame is sealed and molded.

[0005]

In recent years, molded resin molded articles have tended to be thin, but the molded thin resin molded articles have deteriorated in quality such as moisture resistance. ing. Therefore, in order to prevent a decrease in moisture resistance due to a reduction in thickness, an epoxy resin blended in a thermosetting resin material has been improved. Although the above-mentioned improvement in the epoxy resin prevents the above-mentioned decrease in moisture resistance, the adhesion to the mold surface such as the inner surface of the cavity becomes stronger, and therefore, a large amount of the release agent is contained in the resin material. It is being formulated. However, the above-mentioned release agent adheres to the surface of the mold during the resin molding, and exhibits a releasing action. However, the release agent adhered to the surface of the mold has an effect on the surface of the mold. In addition to exerting an oxidizing effect, there is an adverse effect that the mold surface is oxidized (corroded) and the mold surface is easily stained. For example, at the time of resin encapsulation molding, the above-described mold release agent is deposited on the inner surface of the cavity or adheres to other mold surfaces and solidifies, and the mold surface is gradually oxidized by the mold release agent. There is an adverse effect that the surface is easily soiled. Therefore, in each molding cycle, the mold surface is cleaned to remove the release agent from the mold surface, but there is a problem that the release agent cannot be completely removed. Further, for example, at the time of mold rest such as a break time, the mold surface is easily oxidized by the release agent remaining and attached to the mold surface,
Since the mold surface is easily stained, when the resin sealing molding is started again, the mold surface must be cleaned to remove the stain on the mold surface, and the molding can be started immediately. Can not. In other words, there is a problem that the rise in the next molding is slow after the mold is stopped. Therefore, the inventor of the present invention can prevent the mold surface from being oxidized by the release agent attached to the mold surface by exposing the mold surface to an inert gas atmosphere such as nitrogen gas. And completed the present invention.

That is, the present invention relates to a method of releasing a mold surface with a release agent.
Provided is a method for storing a mold for resin sealing molding which prevents oxidation.
The porpose is to do. In addition, the present invention provides
A resin sealing molding method for electronic components that prevents oxidation of the mold surface
The purpose is to provide.

[0007]

Means for Solving the Problems] solutions to technical problems described above
The storage method of the resin molding mold to determine
Resin molding comprising a movable die opposed to the fixed die
In the mold, move the above movable mold in the mold clamping direction.
The middle position of the mold to set the required distance between the mold surfaces of both molds
Performing the placing and moving step, and then at least
In-mold space including pot, resin passage, and cavity
External air shut-off process to shut off the outside part
Then, during the outside air shut-off step, nitrogen
A nitrogen gas supply step of supplying
You.

[0008] Further , the resin sealing molding method for an electronic component according to the present invention for solving the above-mentioned technical problem is directed to a resin sealing molding die including a fixed die and a movable die opposed to the fixed die. A step of supplying a resin tablet for supplying the resin tablet into the disposed pot; a step of supplying a lead frame for supplying and setting an electronic component mounted on the lead frame at a predetermined position of the cavity disposed in the mold; A heating step of the resin tablet for heating the resin tablet supplied into the pot, and a step of closing the inside space of the mold including at least the pot portion, the resin passage portion, and the cavity portion from the outside to shut off the outside air. At the time of the outside air blocking step, at the time of the outside air blocking step, at the step of supplying nitrogen gas for supplying nitrogen gas to the inside space of the mold, at the time of the outside air blocking step, A mold clamping step of clamping and fitting an electronic component on the lead frame to a predetermined position of the mold cavity, and a nitrogen gas supplied to the mold interior space during the outside air shut-off step, Air and moisture remaining in the mold space, air and moisture flowing into the mold space from the inside of the resin tablet heated and expanded during the heating step of the resin tablet, and gases generated by heating. The vacuuming step of the mold space forcibly sucking and discharging to the outside of the mold space, and pressurizing the resin tablet supplied into the pot of the mold, and heating and melting in the pot. A resin sealing molding step of injecting the molten resin material into the cavity through the resin passage portion to resin mold the electronic component on the lead frame fitted in the cavity. To.

[0009]

According to the method of the present invention for storing a resin-sealing molding die.
If, at the time of die rest, placed to face the fixed mold and the fixed mold Yes
At least the position in the resin molding die
In-mold space including a slot, a resin passage, and a cavity
To the outside and nitrogen gas into the space inside the mold.
Because it is a configuration to supply, nitrogen gas
Atmosphere can be set and at least resin
Cavity inner surface, etc. that comes into contact with molten resin material during encapsulation molding
Can be covered under a nitrogen gas atmosphere. Immediately
In other words, the mold surface under the nitrogen gas atmosphere
Efficient control of atmospheric oxygen and moisture
And ensure that the mold surface is exposed to them.
Can be almost eliminated. Therefore,
To the mold surface by the release agent attached to the mold surface
Oxidation can be effectively prevented, and the separation
Efficiently prevents mold surface contamination due to the oxidizing action of the mold agent
The mold can then be stored. The mold surface
Cleaning is unnecessary, so the next molding after the mold is stopped
Sometimes the rise is faster.

Further, according to the method of resin-seal-molding an electronic component of the present invention, mold space is isolated from the outside of including at least the pot portion and the resin path portion and the cavity portion, the nitrogen in the mold space section While supplying the gas, the nitrogen gas supplied to the space inside the mold, air and moisture remaining in the space inside the mold, and the inside of the resin tablet heated and expanded during the heating step of the resin tablet. Since the air and moisture flowing out into the mold space and the gases generated by heating are forcibly sucked and discharged to the outside of the mold space, the mold space described above is used for each molding cycle. The part can be supplied with nitrogen gas, and the mold surface such as the inner surface of the cavity in the mold space can be covered under a nitrogen gas atmosphere. In addition, experiments confirmed that the mold release agent was improved to a state in which the release agent was not easily deposited on the mold surface, and that contamination on the mold surface could be prevented.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a partially cutaway sectional view showing a main part of a mold according to the present invention, and shows a state where the mold is stored. FIG. 2 is a partially cutaway sectional view showing a main part of a mold according to the present invention, and shows a mold open state before resin molding. FIG. 3 corresponds to FIG. 2 and shows a mold clamping state during resin sealing molding.

First, the configuration of the resin molding die used in the present invention will be described. That is, the mold apparatus for resin encapsulation shown in FIGS. 1, 2 and 3 has an upper mold 1 (fixed mold) mounted on an upper fixed board and a lower mold 2 mounted on a lower movable board. (Movable). In addition, the upper and lower molds (1 and 2) are provided with appropriate heating means (9 ) using a heater.
・ 10) are provided respectively. The lower die 2 is provided with a required number of pots 3, and further, a required number of resin molding cavities 5 are provided at lateral positions of the pots 3. A cull portion 7 is provided at a position of the upper mold 1 corresponding to the lower mold pot 3, and an upper mold cavity 6 is provided at a position of the upper mold 1 corresponding to the lower mold cavity 5. Further, the cull portion 7 and the upper mold cavity 6 are connected to each other via a gate 8.
Therefore, in this case, as shown in FIG.
When the mold is clamped, the inside of the pot 3 and the two cavities (5 and 6) are provided so as to be connected to each other through a short resin passage portion including the cull portion 7 and the gate 8. Further, a plunger 4 for pressing the thermosetting resin material R (resin tablet) supplied into the pot 3 is fitted in the pot 3, and the plunger 4 is made of oil.
Appropriate driving means using pressure, pneumatic or electric motor
(Not shown) so as to be moved up and down. Therefore, when the thermosetting resin material R in the pot 3 is pressurized by the plunger 4, the heating and melting of the thermosetting resin material R can be promoted, and the molten resin material in the pot 3 is transferred to the resin passage. It can be injected into the upper and lower cavities (5, 6) through the parts (7, 8). Also,
The upper mold cavity 6 is provided with an air vent 11 for communicating and connecting the two cavities with the outside of the mold when the molds are clamped. Reference numeral 12 in the figure denotes a recess for fitting and setting the lead frame 14 on which the electronic component 13 is mounted, and reference numeral 15 denotes a resin-sealed molded body.

Further, the mold inner space including the pot 3, the resin passage (the cull 7 and the gate 8), the two cavities (5.6), the air vent 11, etc. Is provided so that it can be shut off via an appropriate sealing mechanism. In addition, the outside air blocking range by the above-described sealing mechanism may be, for example, the entire mold apparatus for resin sealing molding, or may be only the entire upper and lower molds (1, 2). Therefore, the outside air cutoff range can be appropriately set.

For example, as the above-mentioned sealing mechanism, a sealing mechanism as shown in FIGS. That is, a round or square cylindrical external air blocking member 16 that covers at least each pot 3 and each cavity 5 on the mold surface of the lower die 2 is fitted on the lower die 2 side. Drives a required drive mechanism (not shown) for the blocking member 16
The lower mold 2 and the outside air blocking member 16 are fitted with a suitable sealing member (not shown) on the fitting surface between the lower mold 2 and the outside air blocking member 16. In addition, a round or square tube that covers at least the resin passage portions (the cull portion 7 and the gate 8), the cavities 6, and the outer periphery of the air vents 11 on the mold surface of the upper mold 1 The outside air blocking member 17 having a shape or the like is fitted therein, and the outside air blocking member 17 is fitted slidably in a mold opening / closing direction via a required driving mechanism (not shown). A suitable seal member (not shown) is interposed and disposed on the fitting surface between the and the outside air blocking member 17. Also, at the time of mold clamping of both molds (1 and 2),
Both outside air shutoff members via both drive mechanisms described above (16, 17)
When each of them is moved forward in the mold clamping direction, the both ends of the outside air shut-off members (16, 17) are provided so as to fit each other (see FIG. 1). In FIG. 1, the upper end of the outside air blocking member 16 fitted to the lower mold 2 is moved up to the vicinity of the mold surface of the lower mold 2 and the outside air blocking member fitted to the upper mold 1 side. 17 illustrates a case where the outer mold 17 is fitted to the outer peripheral surface of the outside air blocking member 16 on the lower mold 2 side.

Further, both outside air blocking members (16, 17) are provided in the outside air blocking range (for example, the mold inner space) formed when both are fitted, and a vacuum mechanism 18 (a pressure reducing mechanism) such as a vacuum pump. Are connected to each other via an appropriate vacuum path 19 such as a vacuum hose. Therefore, air or the like remaining in the outside air cutoff range can be forcibly sucked and discharged by the vacuum mechanism 18, and the outside air cutoff range can be brought into a predetermined vacuum state.

The outside air shut-off range formed when the two outside air shut-off members (16, 17) are fitted to each other is connected to the nitrogen gas supply mechanism 20 via an appropriate supply path 21. . Therefore, high purity (for example, 95
~ 100%) nitrogen gas can be supplied.

Next, a method of storing the mold having the above-described configuration will be described. That is, when the mold having the above configuration is at rest, the upper and lower molds (1 and 2) are in the mold open state. Therefore, first, in the mold open state, an outside air blocking step of forming an outside air blocking range by the sealing mechanism so as to include at least the surface of the mold with which the molten resin material contacts at the time of resin sealing molding is performed. For example, in the mold open state of the two dies (1 and 2), both of the two outside air blocking members (16 and 17) are moved forward in the mold clamping direction, respectively, and the two are fitted together to form the two dies.
An outside air blocking space 22 is formed between the mold surfaces of (1 and 2) (see FIG. 2). At this time, the mold interior space including at least the pot portion 3, the resin passage portion (the cull portion 7 and the gate 8), the two cavity portions (5.6), and the air vent 11 is in a state of shutting off the outside from the outside. Next, a residual air removal step of forcibly discharging and removing air (air) remaining in the outside air blocking space 22 by the vacuum mechanism 18 is performed. Next, a nitrogen gas supply step of supplying nitrogen gas to the outside air blocking space 22 by the nitrogen gas supply mechanism 20 is performed. That is, the nitrogen gas can be efficiently supplied to the outside air blocking space 22, and the inside of the outside air blocking space 22 can be brought into a nitrogen gas atmosphere state. Therefore, the mold surface under the nitrogen gas atmosphere and the oxygen and moisture in the air, which are considered to be a major factor of oxidation, are efficiently and reliably shut off, and the rate at which the mold surface is exposed to these is almost completely reduced. Can be eliminated. That is, since the inside of the outside air blocking space 22 is in an oxygen-free state, the oxidizing action of the release agent attached to the mold surface can be efficiently prevented, and the mold can be stored. Therefore, at the start of molding after the mold is stopped,
No cleaning is required. That is, the start-up becomes early in the next molding after the mold is stopped. In the example shown in FIG. 2, the state where both the outside air shut-off members (16 and 17) are fitted together in the mold open state of the both molds (1 and 2) is illustrated by a two-dot chain line. I have.

Prior to the outside air shut-off step, as shown in FIG. 1, the lower mold 2 is moved upward to set a required space S between both mold surfaces of the two molds (1 and 2). May be performed. That is, first, after performing the above-described intermediate position moving step, both the outside air shut-off members (16, 17) are respectively moved forward in the mold clamping direction, and both are fitted together to form the two molds (1). (2) An outside air blocking step of forming an outside air blocking space 22 between the mold surfaces is performed. At this time, at least the inside space of the mold including the pot portion 3, the resin passage portion, the two cavity portions (5.6), and the air vent 11 is in a state of shutting off the outside from outside. Next, while performing the remaining air removing step of removing the air remaining in the outside air blocking space 22 described above, a nitrogen gas supplying step of supplying nitrogen gas to the outside air blocking space 22 is performed. . That is, by performing the above-described intermediate position moving step, the volume of the outside air blocking space between the two mold surfaces of the two molds (1 and 2) can be reduced, so that nitrogen gas can be supplied efficiently. it can.

The residual air removing step is to reduce the pressure inside the outside air blocking space 22 to facilitate the supply of nitrogen gas. However, the residual air removing step is not always necessary. Therefore, this may be omitted. Further, a configuration may be adopted in which nitrogen gas is continuously supplied to the outside air blocking space 22 when the mold is stopped.

As a method of storing the resin sealing molding die, at least the above-mentioned outside air shut-off step of setting the inside space of the mold to the outside air shut-off state is performed, and the air remaining in the outside air shut-off space 22 is removed. It is also possible to adopt a configuration in which a vacuuming step is performed in which the inside of the space portion 22 is forcibly sucked and discharged to a predetermined degree of vacuum (for example, 1 Torr). In this case, since the outside air blocking space 22 is in an oxygen-free state, the oxidizing action of the release agent on the mold surface can be prevented, and the stain on the mold surface can be efficiently prevented. The mold can be stored.

Next, a case in which the electronic component 13 mounted on the lead frame 14 is molded with a resin using a mold having the above-described configuration will be described. That is, first, FIG.
As shown in (2), the lower mold 2 is moved downward to open the upper and lower molds (1 and 2). Next, when the mold is opened, the thermosetting resin material R (resin tablet) is placed in each pot 3 arranged in the lower mold.
And the lead frame 14 is supplied and set in the setting recess 12 on the mold surface of the lower mold 2. In addition, the resin tablet R supplied into each pot 3 is an upper and lower type.
While being heated and expanded and softened by the heating means (9 and 10) provided in (1 and 2), they are sequentially melted. Next, as shown in FIG.
17) By sliding, both the outside air blocking members are fitted to each other, so that at least the surface of the mold in contact with the molten resin material is brought into the outside air blocking state. That is, the outside air blocking space portion 22 is formed so as to cover at least the pot portions 3, the resin passage portions (7 and 8), the cavity portions (5 and 6), and the outer periphery of each of the air vents 11. Therefore, at least the inside space of the mold is in a state of shutting off the outside from the outside. Next, in the above-described outside air blocking state, the lower mold 2 is moved upward to clamp the upper and lower molds (1 and 2), and the electronic component 13 on the lead frame 14 is moved to the cavity portion (5).・ Set the fitting in the specified position of 6). The above mold clamping is an intermediate mold clamping in which a required space S is formed between the mold surfaces of the upper and lower molds (1, 2) (FIG. 1).
3) and the complete mold clamping in which the mold surfaces of the upper and lower molds (1 and 2) are joined as shown in FIG. 3, and the intermediate mold clamping and the complete mold clamping are performed continuously. Next, nitrogen gas is supplied to the outside air blocking space 22 by the nitrogen gas supply mechanism 20 described above. Next, the vacuum mechanism 20 forcibly sucks and discharges nitrogen gas and the like remaining in the outside air blocking space 22 to which the nitrogen gas has been supplied, and sets the inside of the outside air blocking space 22 to a predetermined degree of vacuum. . At this time, the above-described outside air blocking space 22
Nitrogen gas supplied into the inside and the above-described outside air blocking space 22
Air and moisture remaining in the inside, the above-mentioned outside air blocking space 22
All of the air and moisture inside the resin tablet R flowing out into the (pot 3) and the gases generated by heating the resin tablet R can be forcibly sucked and discharged to the outside of the outside air blocking space 22. . Next, after the upper and lower molds (1 and 2) are completely clamped, a resin sealing molding step of sealing the electronic component 13 on the lead frame 14 in the resin sealing molded body 15 is performed (see FIG. 3). ). In other words, when the upper and lower molds (1 and 2) are fully closed,
The resin tablet R in each of the pots 3 is pressurized by the plunger 4, and the molten resin material heated and melted in each of the pots 3 is passed through the resin passages (7, 8) to the lateral position of each of the pots 3. The electronic component 13 on the lead frame 14 fitted and set in each of the cavities (5, 6) is injected into the required number of cavities (5, 6) provided in the 15 can be sealed. Next, after the required curing time, the upper and lower molds (1 and 2) are opened again, and the upper and lower cavities (5 and
The molded resin 15 and the cured resin in the resin passages (7 and 8) may be released from each other.

Accordingly, nitrogen gas can be supplied to the outside air blocking space 22 at each molding cycle, and the mold surface in the outside air blocking space 22 can be exposed to a nitrogen gas atmosphere. Also, according to experiments, in each molding cycle, when a nitrogen gas is supplied to the outside air blocking space 22 and the mold surface in the outside air blocking space 22 is exposed to a nitrogen gas atmosphere, It was recognized that the release agent was improved to a state where it was difficult to deposit. That is, it was confirmed by experiments that the mold surface could be prevented from being stained by the release agent. Therefore, it is not necessary to clean the surface of the mold every molding cycle.

For example, the setting of the intermediate mold clamping state in the mold clamping process as described above is performed by the lower mold 2 described above.
Without stopping completely, the speed of the mold clamping (elevation of the lower mold 2) from the position of the intermediate mold clamping state (see FIG. 1) to the position of the complete mold clamping state shown in FIG. (Speed) may be set to be performed continuously while decreasing the speed.

Further, after the outside air shut-off step, a configuration may be adopted in which the nitrogen gas supply step and the mold clamping step are performed while the vacuuming step is continued.

The present invention is not limited to the above-described embodiment, but can be arbitrarily and appropriately changed and selected as needed without departing from the spirit of the present invention. is there.

Further, in the above-described embodiment, the case where high-purity nitrogen gas is used has been described. However, the method of the present invention may be carried out using ordinary or low-purity nitrogen gas. In addition, an inert gas such as a helium gas, a neon gas, and an argon gas may be used instead of the nitrogen gas.

[0027]

According to the present invention, according to the present invention, a mold surface is formed by a release agent.
To provide a method for storing molds for resin encapsulation that prevent oxidation of
It has an excellent effect that it can be performed.

Further, according to the present invention, there is an excellent effect that it is possible to provide a resin sealing molding method for an electronic component which prevents oxidation of a mold surface by a release agent.

[Brief description of the drawings]

FIG. 1 is a partially cutaway longitudinal sectional view showing a main part of a mold of a resin molding mold for an electronic component, wherein the mold is in an intermediate clamping state when the mold is stopped, and The outside air shutoff state inside the mold is shown.

FIG. 2 is a partially cutaway longitudinal sectional view showing a main part of a mold for resin sealing molding of an electronic component, in which the mold is opened and a resin sealing molding of an electronic component mounted on a lead frame. This shows the previous state.

3 is a partially cutaway longitudinal sectional view of a mold corresponding to FIG. 2, showing a completely closed state of the mold and a state of resin sealing and molding of an electronic component.

[Explanation of symbols]

1 Upper type 2 Lower mold 3 pots 4 plunger 5 cavities 6 cavities 7 Cull part 8 Gate 11 Air vent 16 Outside air blocking member 17 Outside air blocking member 18 Vacuum mechanism 20 Nitrogen gas supply mechanism 22 Outside air blocking space

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/56 B29C 45/02 B29C 45/14

Claims (2)

(57) [Claims] 1. A fixed type and a movable type disposed opposite to the fixed type.
The movable mold described above,
To the required distance between the mold faces of both molds.
The intermediate position moving step of the mold to be set is performed, and then at least the pot portion and the resin passage in the mold are
Block the space inside the mold including the cavity and cavity from the outside
Performed outside air cutoff step of the outside air cutoff state, when the outside air cutoff step, subjected nitrogen gas into the mold space portion
Resin characterized by performing a supply process of nitrogen gas to be supplied
How to store the mold for sealing. 2. A resin tablet supplying step for supplying a resin tablet into a pot disposed in a resin sealing molding die comprising a fixed die and a movable die opposed to the fixed die, A lead frame supplying step of supplying and setting an electronic component mounted on the lead frame at a predetermined position of the provided cavity section; a resin tablet heating step of heating the resin tablet supplied into the pot; and at least a pot section and a resin passage. A step of shutting off the inside space of the mold including the cavity and the cavity to the outside to shut off the outside air, and supplying nitrogen gas to the space inside the mold during the outside air blocking step. During the gas supply step and the outside air shutoff step, the above-mentioned fixed mold and movable mold are clamped to place the electronic component on the lead frame at a predetermined position in the mold cavity. Mold clamping process of the mold to be mounted, at the time of the outside air blocking process, nitrogen gas supplied to the inside space of the mold, air and moisture remaining in the inside space of the mold, and at the time of heating the resin tablet. The air and moisture flowing out from the inside of the heat-expanded resin tablet to the inner space of the mold, and the gases generated by heating are forcedly discharged to the outside of the inner space of the inner space of the mold. Evacuation step, pressurizing the resin tablet supplied into the mold pot, and injecting the molten resin material heated and melted in the pot into the cavity through the resin passage portion, thereby forming the inside of the cavity. A resin encapsulation step of resin encapsulation of the electronic component on the lead frame fitted on the lead frame.