JP3379221B2 - Resin molded electronic components - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-molded electronic component, and more particularly to a resin-molded electronic component using a TAB tape and a lead frame. 2. Description of the Related Art An electronic component such as a semiconductor device has a high performance while maintaining the external dimensions of an electronic component body, for example, a semiconductor pellet.
In order to achieve high integration, the number of electrodes of the electronic component body is increased to cope with the problem. In general, a lead frame is used in the manufacture of electronic components, and the width and spacing of the leads are set in correspondence with the electrodes of the electronic component body. And lead thickness must be reduced. As a result, the strength of the lead frame decreases, and particularly when the main part including the electronic component body is covered with resin using a molding die after connecting the electronic component body and the lead, the lead frame is deformed by the injection pressure of the resin. However, there is a problem that the electrical connection between the electronic component main body and the lead is damaged, or that an excessively large force is locally applied to the electronic component main body to change the characteristics as an electronic component. Improvements to the mold have been proposed. However, if the number of electrodes is further increased, the width and spacing of the leads must be narrower and narrower.
The strength of the lead frame is further reduced, making it difficult to cope with only the resin mold. Therefore, by etching a conductive foil laminated on an insulating film having a through-hole and connecting a TAB-type electronic component using a TAB tape formed with a conductive pattern including inner leads extending into the through-hole to a lead frame. An electronic component in which the thickness of the lead frame itself is not restricted is known. An example of this will be described with reference to FIG. 6 and FIG. 7 which is an AA plane view of FIG. In the drawing, reference numeral 1 denotes a frame body obtained by punching an insulating tape into a frame shape; 2 denotes a number of inner leads; an intermediate portion of each inner lead 2 is adhered to the frame body 1; The sides extend in parallel with a coarse spacing. The integral body of the frame 1 and the inner lead 2 is obtained from a long TAB tape, but the description of the process is omitted. Reference numeral 3 denotes a semiconductor pellet, which is an electronic component body, and has a large number of protruding electrodes 3a formed on the upper surface. The semiconductor pellet 3 is arranged at the center of the frame 1, and the inner end of the inner lead 2 is superposed on the electrode 3 a and electrically connected. Numeral 4 denotes an island constituting a lead frame (not shown) in which the suspension pins 5 extend from both ends, and the semiconductor pellet 3 with the inner lead 2 connected thereto.
Is fixed. Reference numeral 6 denotes a number of leads constituting a lead frame together with the island 4, and the inner end portion is the island 4
Are arranged in the vicinity. The island 4 bends the middle part of the suspension pin 5 to provide a step with respect to the lead 6.
The outer ends of the inner leads 2 are superposed on the leads 6 and are electrically connected by thermocompression bonding or the like. Reference numeral 7 denotes a resin that covers a main part including the inner ends of the semiconductor pellet 3 and the leads 6. [0004] The resin 7 is coated using dies 8 and 9 of a resin molding apparatus shown in FIG. In the drawing, reference numeral 10 denotes a cavity formed on the abutting surface of the upper and lower molds 8 and 9, and 11 denotes a resin 7a which has flowed into the cavity 10 at one suspension pin 5 position.
And an air vent 12 which communicates with the inside of the cavity 10 at a position facing the gate 11 and discharges the air in the cavity 10 by injecting the resin 7a. The resin 7a supplied from the gate 11 into the cavity 10 travels along the inner wall of the cavity 10 and travels in both the upper and lower directions of the space partitioned by the frame 1 and the inner lead 2. The island 4 and the frame 1 and the inner lead 2 are branched into three layers of the frame 1, the inner lead 2 and the upper mold 9, and the air vent 1
Reaching the second side, the resin filling is completed, and the resin coating is completed.
After that, when the resin 7 is held in a semi-cured state by holding for a predetermined time, the molds 8 and 9 are opened, the resin molded product is taken out, and a tie bar (not shown) to which the lead 6 of the lead frame is connected.
By cutting the outer ends of the suspension pins 5, individual electronic components, that is, semiconductor devices are obtained. Since the semiconductor device 13 has a structure in which the narrow electrode 3a on the semiconductor pellet 3 is connected to the lead 6 of the lead frame via a TAB tape, the number of leads can be increased without unnecessarily reducing the thickness of the lead frame. Can respond. However, in this semiconductor device, the TAB tape narrows the distance between the inner leads 2, so that the resin 7 a does not easily pass between the inner leads 2. Therefore, the resin 7a divided into three layers in front of the semiconductor pellet 3 proceeds as it is, and the resin traveling in the intermediate layer does not intersect with the resin of each of the upper and lower layers, and the intermediate layer branched in two directions in the horizontal plane by the semiconductor pellet 3 The resin 7a does not easily merge even after passing through the semiconductor pellet 3, and air remains between the frame 1, the inner lead 2 and the island 4 located on the air vent 12 side as viewed from the semiconductor pellet 3. The curing of the resin 7a progresses with time even during the resin injecting operation and the viscosity increases, so that the fluidity of the resin decreases. For this reason, the injection pressure is increased at the final stage of resin injection so as to prevent unfilling.
If air remains particularly in the vicinity of the inner lead 2, the residual air is compressed through the inner lead 2 and the inner lead 2 is deformed. As a result, the deformed inner lead 2 may approach the peripheral portion of the semiconductor pellet 3 or come into contact with it in the worst case, causing a withstand voltage defect or a short circuit accident. SUMMARY OF THE INVENTION The present invention has been proposed for solving the above problems, and has an inner end portion of a large number of inner leads whose intermediate portions are connected to a frame made of an insulating material. Is connected to a large number of electrodes formed on the electronic component body, the electronic component body is supported on an island extending from the end with a hanging pin, and one end is disposed in the vicinity of the island. The outer end of the inner lead is electrically connected to the resin-molded electronic component in which the main part including the electronic component body is covered with resin using a resin molding die. Provided is a resin-molded electronic component, characterized in that a through-hole is formed in an opposite portion. By setting the opening diameter of the through hole to 0.5 mm or more, the fluidity of the resin at the time of resin molding can be improved. By forming not only one through hole but a plurality of holes, the shape and dimensions of the lead frame can be improved. The flow direction of the resin can be arbitrarily set according to the above conditions, and the residual air can be eliminated. When a plurality of such through holes are formed, the opening diameter of the through hole near the center of the island is set to be larger than the opening diameter on the peripheral edge side, so that the mechanical strength of the connection portion between the island and the suspension pin is reduced without reducing the air strength. Residuals can be eliminated. Further, by forming a through hole at a position where the through hole overlaps with the electronic component body of the island, it is possible to set both the amount of resin passing and the flow direction as desired. According to the present invention, even if the resin is branched into multiple layers by being divided by the frame, the inner lead and the lead frame in the cavity of the resin molding die, the air vent can be obtained. The resin can smoothly join the layers between the layers, and no bubbles are generated, and a reduction in withstand voltage and a short circuit due to the bubbles can be prevented. An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In the drawings, the same reference numerals as those in FIGS. 6 to 8 denote the same items, and a description thereof will be omitted. The difference between the figures is that the electronic component body, for example, the resin injection portion (gate side) of the island on which the semiconductor pellet 3 is fixed is opposite to the resin injection portion (gate side).
The only difference is that the through-hole 14 is formed in the portion of FIG. In addition, 15
Is a resin covering the main part including the semiconductor pellet 3;
5 'indicates a trace (resin injection portion) of the fluidized resin injected into the cavity of the resin molding die. FIGS. 3 and 4 show the state of resin molding in the process of manufacturing this electronic component (semiconductor device).
It will be explained first. That is, the semiconductor pellet 3 is placed on the island 4.
And a lead frame in which the electrode 3a on the semiconductor pellet 3 and the lead 6 are connected via the inner lead 2 fixed to the frame 1 is sandwiched between upper and lower molds 8 and 9, and the cavity 10 is provided via the gate 11. The fluidized resin 15 is injected into the inside. At this time, the fluidized resin 15 advances toward the air vent 12 along the inner wall of the cavity 10, and before the semiconductor pellet 3, the lower mold 8 and the island 4, the island 4 and the frame 1, the inner lead 2, the frame The resin 15a, 15 is vertically moved by the body 1, the inner lead 2 and the upper mold 9.
The flow is divided into three layers b and 15c. Further frame 1
As shown in FIG. 4, the resin 15b of the intermediate layer which travels between the island and the island 4 is branched in the horizontal plane by the semiconductor pellet 3, and the traveling speed is lower than that of the resins 15a and 15c of the upper and lower layers. Since the distance between the inner leads 2 of the branched intermediate layer resin 15b is as small as several tens of μm, the upper layer resin 15c does not merge with the intermediate layer resin 15b and passes through the side wall of the semiconductor pellet 3. Merges with the lower resin 15a and proceeds to the air vent 12 side. However, since downward force acts on the resin due to gravity, the resin flows into the lower resin 15a side, and not only the progress speed decreases, but also the semiconductor pellet 3 side of the air vent 12 side. There is no force enough to wrap around the side wall of the semiconductor pellet 3, and the back side of the semiconductor pellet 3 is in a depleted state without the resin of the intermediate layer. Therefore, at this time, the resin 15 along the upper and lower molds
a and 15c precede the intermediate layer resin 15b. Since the resin 15a between the island 4 and the lower mold 8 exerts pressure on the wall surfaces of the island 4 and the lower mold 8, when the resin 15a advances and reaches the position of the through hole 14 which is a feature of the present invention, The resin 15a flows between the frame 1, the inner lead 2 and the island 3 through the through hole 14, covers the back side of the semiconductor pellet 3, and fills the depletion region. Merges with the resin 15b of the intermediate layer. When the upper and lower layers of the resin 15a, 15c deviate from the lower surface of the island 4 and the upper surface of the inner lead 2, the cross-sectional area of the opening increases, so that the traveling speed decreases rapidly and proceeds along the wall surfaces of the molds 8, 9, Although a force for lifting the resin upward from the terminal end of the island 4 cannot be expected, the resin in contact with the island 4 is subjected to an injection pressure, so that the resin is continuously extruded from the through hole 14 and the resin is filled into the depletion region. Is continued. In this manner, the resin can be filled in the cavity 10 without retaining the air between the frame 1, the inner leads 2 and the island 4. Thereby, in the final stage of the resin injection, no air remains in the inner lead 2 even if the injection pressure is increased, so that there is no inclination of the frame 1 and no deformation of the inner lead 2.
Accidents such as reduced withstand voltage and short circuit can be prevented. This through hole 1
If the opening diameter of 4 is small, the flow of resin cannot be improved even if a large number of holes are drilled and the total opening area is set large, so the diameter is desirably set to 0.5 mm or more.
The maximum diameter can be set within a range that does not hinder the support of the semiconductor pellet 3. In the illustrated example, a single through hole 14 is shown, but by forming a large number of holes, bubbles can be removed well. In this case, by setting the diameter closer to the center of the island 4, that is, the upstream side in the traveling direction of the resin, to be larger, and the through hole on the island 4 side to be smaller, it is possible to supply the resin having a high injection pressure to the through hole 14. The through hole 14 is formed so as to partially overlap the back surface of the semiconductor pellet 3, so that the resin 15 a along the lower mold 8 is inserted into the through hole 14 from the lower surface of the island 4 as shown in FIG. The flow direction of the resin can be set in the direction indicated by the arrow in the drawing with the lower surface 3b of the semiconductor pellet 3 and the inner wall 14a of the through hole 14 on the air vent side, so that the area surrounded by the back side of the semiconductor pellet 3 and the frame 1 and the inner lead 2 can be efficiently used. Good resin filling. Further, in the above embodiment, the through hole 14 is formed on the island 4 on the side opposite to the resin injection portion 15 ′ as viewed from the semiconductor pellet 3, but not only on the portion adjacent to the suspension pin 5 but also on the peripheral surface of the semiconductor pellet 3. Many can be formed along. The electronic component body 3 may be a device in which a large number of electronic components including a semiconductor pellet are mounted on an insulating substrate and are externally connected by a large number of leads, in addition to the semiconductor pellet alone. As described above, according to the present invention, even if a region where the flow of the resin between the inner lead and the island is hindered due to the increase in the number of leads and a region where the resin is difficult to be filled is formed, the predetermined number of the islands can be obtained. By providing the through hole at the position, the resin can be efficiently guided to this region, and the retention of bubbles can be prevented. Therefore, it is possible to prevent a decrease in withstand voltage and a short circuit accident due to deformation of the inner lead.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional plan view showing an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line CC of FIG. 1. FIG. FIG. 4 is a cross-sectional view taken along line DD of FIG. 3; FIG. 5 is a cross-sectional view of a main part showing a modification of the through hole; FIG. 6 is a cross-sectional plan view of an electronic component which is a premise of the present invention; 6 is a sectional view taken along the line AA of FIG. 8 FIG. 8 is a sectional view taken along the line BB explaining the resin molding work of the electronic component shown in FIG. 6 [Description of References] 1 Frame 2 Inner lead 3 Semiconductor pellet 3a Electrode 4 Island 5 Hanging pin 6 Lead 14 Through hole 15 Resin 15 'Resin injection part

Claims (1)

(57) [Claims 1] The inner ends of a large number of inner leads whose intermediate portions are connected to a frame made of an insulating material are connected to a large number of electrodes formed on an electronic component body. Then, the electronic component body is supported on an island on which a suspension pin extends from an end, and one end is electrically connected to a number of leads arranged near the island and the outer end of the inner lead. In a resin-molded electronic component in which a main part including the electronic component body is covered with a resin by a resin molding die, a part of an opening surface is provided on a part of an opening surface opposite to a resin injection portion of the island.
A resin-molded electronic component, wherein a through- hole whose edge overlaps is formed.