JPH1126684A - Lead frame and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation of leads owing to the foreign matters of resin fine powders at the time of forming resin, and to dissolve the troubles by short-circuiting electronic parts and the drop of withstand voltage, by connecting the leads between idle ends on both faces of the semiconductor pellet mount of the leads and tie bars by means of connection resin from both faces of the semiconductor pellet mount. SOLUTION: In a lead frame 13, an island 4 on which an electronic part main body is mounted is arranged in a frame 2 through hanging pins 5, multiple leads 6 are laid toward the island 4 from the frame 2, and the leads 6 and 6 between the idle ends of both sides of the semiconductor pellet mount of the leads 6 and the tie bars 7 in the lead frame 2 where the intermediate part of the respective leads 6 are connected by connection resin 14 from both sides of the semiconductor pellet mount. Connection resin 14 is filled between the leads 6 and 6 so that it is not exposed to both sides where the pellet is not mounted. Thus, the deformation of the lead owing to the foreign matters of resin fine powders can be prevented at the time of forming resin, and the short circuit of the electronic part and the drop of withstand voltage can be dissolved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame covered with a resin mold, and more particularly to a lead frame suitable for a multi-lead semiconductor integrated circuit device.

[0002]

2. Description of the Related Art An example of an electronic component such as a semiconductor integrated circuit device will be described with reference to FIG. In the drawing, reference numeral 1 denotes a lead frame having a structure shown in FIG. 6, in which an island 4 on which an electronic component body 3 such as a semiconductor pellet is mounted via a suspension pin 5 in the frame 2, and from the frame 2 toward the island 4. A large number of leads 6 are extended, and intermediate portions of the leads 6 are connected by tie bars 7. Using the lead frame 1, the electronic component main body 3 is first mounted on the island 4, and the electrodes (not shown) on the electronic component main body 3 are connected to the free ends of the leads 6 by wires 8. An area surrounded by the tie bar 7 is covered with a sealing resin 9, and unnecessary portions such as the tie bar 7, the frame 2, and the hanging pins 5 exposed from the resin 9 are cut and removed to obtain individual electronic components. This resin sealing is performed using a pair of resin molds 11 and 12 having a cavity 10 formed in an abutting surface as shown in FIG. 7, and the mounting of the electronic component body 3 and the connection work of the wire 8 are completed. A region surrounded by the tie bar 7 is arranged in the cavity 10 and clamped,
This is performed by injecting the fluidized resin 9 into the cavity 10. After the resin 9 is solidified in the cavity 10, the molds 11 and 12 are opened, the resin-molded lead frame 1 is taken out, and the mold is cleaned to remove residues such as resin fragments. repeat. Electronic components having such a structure are miniaturized in response to demands for miniaturization and high functionality of electronic circuit devices and the like. If the number of leads needs to be increased due to high integration etc. even for the same dimensions, the width and spacing of the leads are reduced, and the thickness of the leads is also possible to make the leads narrower. It is set to be thin. The lead 6 is made of a sealing resin 9
The intermediate portion or the outer end portion exposed from the
Within, the distance between each other is reduced toward the island 4,
The inner end is arranged close to the electrodes of the electronic component body 3 so that the wires 8 connecting the electrodes and the leads have substantially the same length. For example, when the lead 4 has a 15 mm square and 300 leads, the lead thickness is set to 0.2 mm, the lead width is set to 0.15 mm, and the interval between the lead ends is set to 0.2 mm. By the way, when an external force is applied to the lead frame 1 during supply or removal of the lead frame 1 to or from the transfer device and wire bonding causes deformation to remain, the lead 6 bends, and its tip comes into contact, causing an electrical short circuit. For this reason, there is a lead frame in which a frame-shaped heat-resistant film (not shown) is attached between the tip of the lead 6 and the tie bar 7 to prevent deformation, but the frame-shaped heat-resistant film is not only made of a material but also made of a lead. At the time of manufacturing the frame 1, the ends of the leads 6 are commonly connected by connecting strips (not shown) so that the intervals between the individual leads are not shifted, a frame-shaped heat-resistant film is attached, and then the connecting strips must be cut and removed. The work is complicated and expensive. for that reason,
Care is taken in the handling of the lead frame 1 so that the lead frame 1 is supplied to the mold without bending.

[0003]

However, even if the lead is supplied to the mold in a state where the lead is not bent before molding of the resin, after the molding of the resin, a short-circuit or a withstand voltage of 1,000 or less parts is reduced. It occurred at a rate of one in 20,000. A visual inspection of the resin molded product having the bent lead using a microscope revealed fine dents on the lead 6 derived from the resin 9. In addition, some resin fragments were attached to form dents, and the dents were determined to be due to the resin fragments. However, since the lead bending defect still occurs, the process of the resin molding operation was reviewed in detail, and the fine powder of the resin adhered to the resin tablet (not shown) supplied to the mold after the mold cleaning was removed. It was found that it adhered on the mold and on the lead frame and this became resin foreign matter. Since the fluidity of the resin varies greatly depending on the amount of water contained in the resin tablet, it is usually packed in waterproof bags in multiple units and stored at low temperature, so that the water is confined in the resin and returned to room temperature before use. When they are rubbed against each other during movement in a bagged state, fine resin powder is produced. This fine powder can be easily removed with an air blower, but at the same time the surface moisture is removed, and if dried, the fluidity of the resin in the mold will vary greatly. The separation of the fine powder attached to the tablet surface was inevitable. In a model with a lead width of 0.5 mm, a lead arrangement interval of 0.7 mm, and a lead thickness of 0.2 mm, even if resin fine powder adheres to the lead, the displacement caused by deformation of the lead is small and causes little problem. It has also been found that when a resin fragment having a large diameter is caught between the leads, the resin fragment pressed by the mold pushes and spreads the lead, and the expanded lead approaches or comes into contact with an adjacent lead, resulting in a failure.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, and an island on which an electronic component body is mounted is arranged in a frame via a suspension pin, and is moved from the frame toward the island. In a lead frame in which a large number of leads are extended and the intermediate portions of the leads are connected by a tie bar and a region surrounded by the tie bar in the frame is covered with a sealing resin, the semiconductor pellet mounting surface of the lead The lead between the free end on the side and the tie bar is connected by a connecting resin from the semiconductor pellet mounting surface side.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A lead frame according to the present invention
The lead between the free end of the lead on the semiconductor pellet mounting surface side and the tie bar is connected by a connecting resin from the semiconductor pellet mounting surface side, but the connecting resin is exposed on the pellet non-mounting surface side. Do not fill between leads to avoid. Further, the lead frame manufacturing apparatus according to the present invention arranges an island on which an electronic component body is mounted in a frame via a suspension pin, extends a large number of leads from the frame toward the island, and intermediates each lead. Frame connecting means to move the lead frame whose area surrounded by the tie bar in the frame is covered with the sealing resin by moving the semiconductor pellet mounting surface downward, Liquid resin is extruded in a rectangular frame shape, and is provided below the fixed position of the movement path of the lead frame, and is provided with connection resin supply means which is relatively close to and separated from the lead frame. Press the rectangular frame-shaped liquid resin against the lead intermediate part of the lead frame to connect the leads with the resin. And butterflies. In this device, it is possible to provide a spacer for regulating the distance between the frame of the lead frame and the upper surface of the connection resin supply means.
Further, in this apparatus, after scraping the liquid resin remaining on the upper surface of the connection resin supply means, the liquid resin can be supplied in a constant amount.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lead frame according to the present invention will be described below with reference to FIGS. In the figure, the same components as those in FIG. 6 are denoted by the same reference numerals, and redundant description will be omitted. In a lead frame 13 according to the present invention, an island 4 on which a main body of an electronic component such as a semiconductor pellet is mounted is arranged via a suspension pin 5 in a conventional lead frame 1, that is, a frame 2, and from the frame 2 toward the island 4. Between the leads 6 and 6 between the free end of the lead 6 on the semiconductor pellet mounting surface side of the lead frame and the tie bar 7 of the lead frame in which a large number of leads 6 are extended and the intermediate portions of the leads 6 are connected by tie bars 7. Are connected by a connecting resin 14 from the semiconductor pellet mounting surface side. As shown in FIG. 2, the connecting resin 14 is filled between the leads 6 so as not to be exposed on the non-pellet mounting surface side. An apparatus for manufacturing the lead frame 13 will be described with reference to FIG. In the drawing, reference numeral 15 denotes a lead frame transporting means for moving the lead frame 1 with its semiconductor pellet mounting surface facing downward, and reference numeral 16 denotes a connecting resin supply means, which is disposed below a fixed position of a moving path of the lead frame 1 and moves up and down. And relatively close to and separated from the lead frame 1. The connecting resin supply means 16 is a block 1 having a resin reservoir 17 formed therein.
4, a substantially rectangular frame-shaped groove 19 is formed as shown in FIG. 4, and the groove 19 and the resin reservoir 17 are communicated with each other to push up the liquid resin 14 a from the resin reservoir 17. The shape protrudes in a substantially rectangular frame shape. In this apparatus, the connecting resin supply means 16 is moved up and close to the lead frame 1 stopped at a fixed position, and the rectangular frame-shaped liquid resin 14 is moved.
a is pressed against the intermediate portion of the lead 6, and the leads 6 are connected to each other by the resin 14a. At this time, the projecting height of the liquid resin 14a and the distance between the block 18 and the lead frame 1 are set so that the liquid resin 14a does not protrude to the electronic component non-mounting surface side of the lead frame 1, and the lead is placed in the state shown in FIG. 6 and 6 are connected by a connecting resin 14. In the lead frame 13 manufactured as described above, since the intermediate portion of the lead 6 is connected by the connection resin 14, the resin fine powder and the fragments adhere to the portion held by the mold during the resin molding. Even if the lead is bent, the deformation of the connecting resin 14
And it does not reach the tip of the lead 6. Therefore, the lead thickness is thin, the lead width is narrow, the lead is easily deformed, and even in a lead frame in which the lead arrangement interval is narrow, it is possible to reliably prevent a short circuit and a withstand voltage decrease due to an unwanted lead bending in a resin molding process. I can do it. When the resin is molded into the lead frame, the connection resin 14 protrudes toward the wire connection surface of the lead 6 and becomes an obstacle to the liquid resin injected into the mold, so as to reduce the injection pressure of the resin. Wire deformation due to flowing resin can be prevented. Also, in the electronic component using the lead frame 13 according to the present invention, since the connecting resin 14 integrally connects the intermediate portion of the lead 6, the lead 6 can be securely fixed when the wire is ultrasonically bonded to the lead. Can be connected securely. Further, in the electronic component using the lead frame 13, the lead 6 is double-coated with the coupling resin 14 and the exterior resin, so that the moisture resistance is also improved.

[0007]

As described above, according to the present invention, deformation of the lead due to foreign matter such as fine resin powder during resin molding can be prevented, and an electronic component free from short-circuit and withstand voltage reduction can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view showing a part of a lead frame according to an embodiment of the present invention.

FIG. 2 is a sectional view of the lead frame taken along line AA of FIG. 1;

FIG. 3 is a front sectional view of a manufacturing apparatus for explaining a manufacturing method of the lead frame in FIG. 1;

FIG. 4 is a top view of the connecting resin supply means of the apparatus shown in FIG. 3;

FIG. 5 is a partial cross-sectional side view showing an example of an electronic component.

FIG. 6 is a partial plan view showing an example of a lead frame used for manufacturing an electronic component.

FIG. 7 is a side sectional view of a resin molding die used for resin coating of an electronic component.

[Explanation of symbols]

 2 Frame 3 Electronic component body 4 Island 5 Hanging pin 6 Lead 7 Tiba 13 Lead frame 14 Resin for connection

Claims (5)

[Claims] An island on which an electronic component body is mounted is arranged in a frame via a suspension pin, a number of leads extend from the frame toward the island, and intermediate portions of the leads are connected by a tie bar. In a lead frame in which a region surrounded by a tie bar in a frame is covered with a sealing resin, a lead between the free end of the lead on the semiconductor pellet mounting surface side and the tie bar is connected from the semiconductor pellet mounting surface side. A lead frame, which is connected with a resin for use. 2. The lead frame according to claim 1, wherein the connecting resin is filled between the leads so as not to be exposed on the non-pellet mounting surface side. 3. An island on which an electronic component body is mounted in a frame via a suspension pin, a number of leads extending from the frame toward the island, and a middle portion of each lead connected by a tie bar. A lead frame conveying means for moving a lead frame whose area surrounded by a tie bar in the frame is covered with a sealing resin with its semiconductor pellet mounting surface facing downward, and a fixed amount of liquid resin on a top surface in a rectangular frame shape. Connecting resin supply means disposed below the fixed position of the moving path of the lead frame and relatively close to and separated from the lead frame. A lead frame manufacturing apparatus characterized in that a resin is pressed against a lead intermediate portion of a lead frame and each lead is connected with the resin. Place. 4. The lead frame manufacturing apparatus according to claim 3, wherein a spacer for regulating a distance between the frame of the lead frame and the upper surface of the connection resin supply means is arranged. 5. The lead frame manufacturing apparatus according to claim 3, wherein a fixed amount of the liquid resin is supplied after scraping off the liquid resin remaining on the upper surface of the connection resin supply means.