JPH07231005A - Inspecting method for uncharging of molded part for package type electronic element - Google Patents

Abstract

PURPOSE:To inspect the uncharging condition of a synthetic resin in a molded part forming die by checking by a light-transmission type sensor whether any void exists or not in a part adjacent to an air vent formed at the die among synthetic resin burrs formed at a part of the side face of the molded part. CONSTITUTION:If a synthetic resin is poorly charged in a molded part forming cavity, voids 20 grow in inlet parts of synthetic resin burrs 19a and 19b to air vents 15. The existence of the voids 20 is detected by a light transmission type sensor 21 disposed at the downstream of a forming die in a carrying passage for a lead frame 1. By a signal from the sensor 21, whether or not any space not charged with the molten synthetic resin remains in the forming cavity is surely detected during carrying the lead frame 1 at forming of a molded part. Thus, the void condition in the molded part can be inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package type electronic component in which an element such as a semiconductor chip is packaged in a synthetic resin mold portion, and the synthetic resin mold portion is formed by a transfer molding method. The present invention relates to a method for detecting an unfilled state of synthetic resin generated in the mold portion when molded by.

[0002]

2. Description of the Related Art In an electronic component such as a transistor or a diode, a synthetic resin mold portion for packaging a portion of the element is formed by a pair of upper and lower metal molds for the lead frame during transfer of the lead frame in the longitudinal direction. The synthetic resin is molded by a transfer molding method in which a synthetic resin is press-fitted in a molten state in a cavity for molding in a mold part formed by recessing the mating surfaces of the two molds. Insufficient, the stroke of the plunger that presses the raw material resin is insufficient, the injection gate is clogged into the molding cavity, and the resin is cured during injection into the molding cavity. Due to this, a state of insufficient filling of the synthetic resin into the molding cavity is generated, It is chipped part of the external shape of the part, or there are large voids inside the molded part, or adhesion to a lead terminal of the synthetic resin will lowered.

Therefore, conventionally, the external shape of the molded portion after being molded by the transfer molding method is photographed by a camera or the like during the transfer of the lead frame, and the image is processed to obtain the image of the molded portion. By judging whether or not the external shape is a preset external shape, it is inspected whether or not the synthetic resin is not filled in the mold portion.

[0004]

However, this inspection method requires a complicated algorithm such as photographing the outer shape of the mold portion, processing the photographed images, and comparing the processed images. As a result, the transfer speed of the lead frame must be slowed down or the images must be taken by a plurality of cameras, resulting in a significant increase in cost.

Moreover, there is a problem that it is not possible to sufficiently check the state of bubbles inside the mold part and the adhesion of the synthetic resin to the lead terminals only by checking the external shape of the mold part. INDUSTRIAL APPLICABILITY The present invention makes it possible to very easily inspect an unfilled state of a synthetic resin in a mold part for packaging a part of an element such as a semiconductor chip in an electronic component without causing the problems as described above. It is a technical task to provide a method.

[0006]

In order to achieve this technical object, the present invention provides "a part of an element in each electronic component in a path for transferring a lead frame used for manufacturing an electronic component along its longitudinal direction. At a location behind the molding step of the synthetic resin mold part to be packaged, among the synthetic resin burrs formed on a part of the side surface of the mold part, to the air vent provided in the molding die of the mold part. The light transmissive sensor detects whether or not there is a cavity in the adjacent area. "

[0007]

[Operation] Generally, molding of the mold part is performed by molding a synthetic resin in a molten state from an injection gate communicating with one end of the mold part into the mold part molding cavity formed by recessing the mating surfaces of both molds. The air in the cavity is injected into the atmosphere while being released into the atmosphere from an air vent having a minute cross-section communicating with the other end, and when the molten synthetic resin reaches the air vent, The molten synthetic resin is clogged at the inlet to the air vent and stops flowing out from the air vent, so that the molten synthetic resin is thereafter pressurized to a high pressure,
The process of curing in this pressurized state is performed.

When the molten synthetic resin is filled in the cavity, the raw material resin is insufficient, the stroke of the plunger for pressing the raw material resin is insufficient, the injection gate is clogged in the molding cavity, and the mold portion is filled. When insufficient filling of the synthetic resin into the molding cavity occurs due to resin curing during injection into the molding cavity, a cavity is formed in the air vent.

That is, when a cavity is formed in the air vent portion, it means that the filling of the molten synthetic resin into the cavity is incomplete. At this time, it is impossible to pressurize to a high pressure, It is expected that a part of the mold part may be chipped, large air bubbles may exist in the mold part, or that the synthetic resin in the mold part is not sufficiently adhered to the lead terminals. It

Therefore, as described above, among the synthetic resin burrs formed on a part of the side surface of the mold portion, there is a cavity in the portion adjacent to the air vent provided in the molding die of the mold portion. By detecting whether or not it is a light transmission type sensor, by the signal from this light transmission type sensor, at the time of molding of the mold part, the filling of the molten synthetic resin into the cavity for molding the mold part is not filled. Whether or not there is a state can be reliably detected during the transfer of the lead frame.

[0011]

As described above, according to the present invention, it is possible to determine whether or not there is an unfilled state of the synthetic resin when molding the mold portion of each electronic component in the lead frame.
Since it can be detected after the molding of the molded part, this detection can not only check the external shape of the molded part, but also the state of bubbles inside the molded part and the adhesion of the synthetic resin to the lead terminals. It is also possible to inspect, and moreover, by performing the above-mentioned detection by a light transmission type sensor, much more than in the conventional case in which this image is processed after the appearance shape of the mold part is photographed. Since the detection can be performed in a short time and the transfer speed of the lead frame can be increased, the cost required for this can be significantly reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings of FIGS. In the figure, reference numeral 1 indicates a hoop-shaped lead frame which is transported in the longitudinal direction as indicated by an arrow A. The lead frame 1 connects the pair of left and right side frames 2 and 3 to each other. At least a pair of lead terminals 5 and 6 that constitute one electronic component are integrally formed in a portion between the section bars 4 along the longitudinal direction at appropriate pitch intervals. A semiconductor chip 7 is mounted on the tip of one of the lead terminals 5 of 6, and the semiconductor chip 7 and the tip of the other lead terminal 6 are electrically connected by wire bonding with a metal wire 8. ing.

In the transfer path of the lead frame 1,
A pair of upper and lower molding dies 9, 10 are arranged so as to sandwich the lead frame 1, and the lead terminals 5, 5 of the lead frame 1 are provided on the mating surfaces of the molding dies 9, 10. Mold portions forming cavities 11 and 12 are formed in each of the six positions, and the upper surface of the lower mold 9 of the molding dies 9 and 10 is formed along one side edge of the lead frame 1. Runner groove 13 that extends
An injection gate 14 that communicates the runner groove 13 with one end of each of the cavities 11 is engraved. Furthermore, the lower surface of the upper mold 10 of the molding molds 9 and 10 has the above-mentioned structure. Air vents 15 having a minute cross-sectional area and communicating with the other end of the cavity 12 are formed on the left and right sides of the other lead terminal 6, respectively.

Then, a raw material resin 17 is loaded into a raw material loading chamber 16 which is formed in the upper die 10 so as to communicate with the runner groove 13 in the lower die 9, and the raw material resin 17 is melted. By injecting the plunger 18 into the raw material loading chamber 16, the molten synthetic resin passes through the runner groove 13 and communicates therewith.
While the air is injected into each of the cavities 11 and 12 through the air, the air in each of the cavities 11 and 12 is released into the atmosphere from the air vent 15 for each of the cavities 11 and 12. And a mold part 1 for packaging the tip parts of both lead terminals 5 and 6.
9 can be molded. In this case, the synthetic resin burr 19 having the same thickness as that of the lead frame 1 is provided on both left and right sides of the other lead terminal 6.
Therefore, a and 19b are simultaneously molded.

That is, the molding of the mold portion 19 is performed as follows.
A synthetic resin in a molten state is injected from an injection gate 14 communicating with one end of the cavity 11, 12 into a molding portion forming cavity 11, 12 formed in a concave shape on the mating surfaces of the molding dies 9, 10. The air in the cavities 11 and 12 is injected into the atmosphere while being discharged into the atmosphere from an air vent 15 having a minute cross-section communicating with the other end, and the molten synthetic resin reaches the air vent 15 part. When it reaches this molten synthetic resin, the air vent 1
5 is blocked at the inlet to 5 and stops flowing out of the air vent 15, so that the molten synthetic resin is pressed to a high pressure by the further pushing of the plunger 18, and the pressurized state is maintained. It takes the process of curing with.

The cavities 11, 1 of this molten synthetic resin
When filling the inside of 2, the raw material resin is insufficient, the stroke of the plunger 18 that presses the raw material resin is insufficient, the injection gate 14 is clogged into the mold portion molding cavities 11 and 12, and the mold portion molding cavity. 11,
When the synthetic resin is insufficiently filled in the molding cavity 11 or 12 due to the curing of the resin during the injection into the inside 12, the air vents 15 are filled with the resin shown in FIG. As shown by the dotted line, the cavity 20
You will be able to

Therefore, the presence / absence of the cavity 20 is detected by a light-emitting element 21a and a light-receiving element 21b which are arranged in a portion of the transfer path of the lead frame 1 behind the molding dies 9, 10. The transmissive sensor 21 is used for detection. As a result, the signal from the light transmissive sensor 21 causes the molded portion 19 to
When molding, the cavity 1 for molding the mold part
It is possible to reliably detect whether or not there is an unfilled state in the filling of the molten synthetic resin into the insides of 1 and 12 during the transfer of the lead frame 1.

That is, when molding the mold portion 19, of the synthetic resin burrs 19a and 19b simultaneously molded on a part of the side surface of the mold portion 19, each air vent provided in the molding dies 9 and 10. The light transmissive sensor 21 detects whether or not the cavity 20 exists in the portion adjacent to the mold portion 1,
Not only can the external shape of 9 be inspected, but also the state of bubbles inside the mold part 19 and the adhesion of the synthetic resin to the lead terminals 5, 6 can be inspected.

In the above embodiment, the synthetic resin burrs 19a and 19b generated at the time of molding the mold portion 19 are molded by the one side frame 3 and each section bar 4 of the lead frame 1. The present invention is not limited to this, the synthetic resin burr in the molding portion is formed by a dam bar integrally provided between the lead terminal and the section bar, or when there are a plurality of lead terminals, It goes without saying that the present invention can also be applied to the case of molding with a dam bar integrally provided between the lead terminals.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is a plan view taken along the line III-III in FIG.

FIG. 4 is a cross-sectional view of a lead frame sandwiched between a pair of molding dies.

FIG. 5 is a cross-sectional view of a state in which a mold portion is being molded.

6 is an enlarged sectional view taken along line VI-VI of FIG.

FIG. 7 is a plan view of FIG.

[Explanation of symbols]

 1 lead frame 2,3 side frame 4 section bar 5,6 lead terminal 7 semiconductor chip 8 metal wire 9,10 molding die 11,12 mold cavity 13 runner groove 14 injection gate 15 air vent 16 raw material Loading chamber 18 Plunger 19 Mold part 19a, 19b Synthetic resin burr 20 Cavity 21 Light transmission type sensor

Claims (1)

[Claims] 1. A portion of a path for transporting a lead frame used for manufacturing an electronic component along its longitudinal direction, which is behind a molding step of a synthetic resin mold portion for packaging a portion of an element in each electronic component, Among the synthetic resin burrs formed on a part of the side surface of the mold portion, a light transmissive sensor determines whether or not there is a cavity in a portion adjacent to the air vent provided in the molding die of the mold portion. A method for inspecting unfilling of a mold part in a package type electronic component, which is characterized in that