JPH1168007A - Lead frame for semiconductor device and molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid leaving a runner in dies by providing protruding means on section bars of a semiconductor lead frame having the section bars for coupling islands for mounting a semiconductor chip and leads for taking out semiconductor chip electrodes. SOLUTION: For the resin sealing, an upper die 6 is put up, a chip-mounting lead frame 1 is set on a lower die 7, the upper die is lowered to fix the lead frame 1 such that a protrudent blade 8-1 provided at a runner contact face 8 of the upper die 6 presses section bars 2 to automatically form protrusions 3 at portions to contact runners 4 of the bars 2 and hence a resin is polymerized to harden with the protrusions 3 intrude in the runners 4 and the lead frame 1 never separates from the runners 4 to avoid leaving the runners 4 in the die when the mold die 5 is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a mold for mounting a semiconductor device, and more particularly to a lead frame and a mold that do not leave resin residue on the mold.

[0002]

2. Description of the Related Art A resin molding method is widely used to protect a semiconductor chip from the outside. In recent years, when a large-sized IC having a large number of pins and a large package size is used for a logic, particularly for a gate array, a molding method corresponding to a large chip and a large package is required. As a method of molding with resin, a transfer mold that is large in quantity that can be molded at one time and inexpensive is mainly used. In the transfer molding method, the number that can be molded at one time is
The number of molds has increased from several tens to several hundreds, and the size of the mold has been increased in order to improve productivity.

FIG. 3 is a side view showing an example of a conventional general molding apparatus for performing transfer molding.
In this device, a frame is inserted between the upper and lower molds 6 and 7, and resin is injected between the upper and lower mold chase 25 by the hydraulic plunger 23. This is a mechanism in which the resin is filled into the cavity 10 contained in the chase 25 and the molding of the semiconductor device is completed. The movable platen 2 above and below the upper die 6
2 is performed by moving up and down along the guide 24.

A transfer molding process using such a molding apparatus is performed according to the following procedure shown in FIGS. 1) Preheating of the dies The dies 6 and 7 are provided with heaters 26 provided in advance in the dies.
Is heated by.

2) Setting of lead frame The upper die 6 is raised, and the lead frame 1 on which the bonded semiconductor chip 9 is mounted is placed on the lower die 7 as shown in FIG. Lower the lead frame 1 to fix it.

3) Injecting the resin As shown in FIG. 5, the resin tablet 28 is heated by the high frequency preheater 27 or the like to lower the resin viscosity, and then is injected into the pot 11 in the dies 6 and 7 as shown in FIG. The resin is also heated by the molds 6 and 7 so that the viscosity is further reduced.

4) Injecting resin As shown in FIG. 7, the plunger 23 is lowered, and the resin is injected from the pot 11 into each cavity 10 through the runner 4. FIG. 10 shows a perspective view of the resin injected into the molds 6 and 7 at this time. At this time, no pressure is applied during the injection, and the pressure is applied after the resin is substantially filled in the cavity 10. At this stage, when the resin is melted, air is easily entrained. The resin is injected into the cavity 10 via the runner 4 together with the entrained air. However, when pressure is applied, air is exhausted or reduced.

5) Curing of Resin When the resin is filled and held for several minutes, the resin polymerizes and cures. In order to increase the productivity, it is desirable to shorten the curing time in this step as much as possible to increase the index. It is product reliability and workability that determine the curing time.

6) Removal of the semiconductor device When the molding is completed, the upper mold 6 is raised as shown in FIG.
The semiconductor device (IC) 12 and the runner 4 are taken out. Thereafter, as shown in FIG. 9, the IC 12 is separated from unnecessary parts such as the runner 4 and the cull 13 under the plunger, and the unnecessary parts are discarded.

[0010] 7) Final cure At the stage of 6), acceptance has not yet been completed and the resin properties have not been stabilized.
Complete the reaction. Generally, heating is performed at a temperature of about 160 ° C. to 180 ° C. for several hours.

As described above, conventionally, the semiconductor lead frame 1 is, as shown in FIG.
Was sealed in the cavity 10 via the runner 4 in a resin sealing step for sealing the resin. In order to further improve the productivity, a plurality of semiconductor chips 9 are mounted on one lead frame 1 so as to extend over a plurality of cavities 10 and a plurality of runners 4 as shown in FIGS. One lead frame 1 is sealed.

In such a case, the conventional lead frame 1
Then, after resin sealing, the lead frame 1
When taking out, there is a possibility that a problem may occur that the resin remains in the mold at the runner 4 as shown in FIG. If the work is continued without noticing this, there is a problem that the remaining runner 4 hinders the resin charging path at the time of resin charging in the next cycle, leaving a cavity 10 in which no resin is charged. Occurs.

[0013]

As described above, when a semiconductor device is formed using a conventional lead frame for mounting a semiconductor device and a mold, the resin remains in the mold at the runner portion. There is a possibility that a problem may occur and productivity may be impaired.

According to the present invention, there is provided a lead frame in which the resin is sealed, and after removing the lead frame from the mold, no resin remains on the runner portion. The aim is to provide a mold that can be realized.

[0015]

In order to achieve the above object, the present invention provides a semiconductor device having an island portion for mounting a semiconductor chip, a section bar portion connecting the island portion, and a lead portion for taking out a semiconductor chip electrode to the outside. In the device lead frame, a projection means is provided on the section bar portion.

Also, a resin device lead frame having an island portion for mounting a semiconductor chip, a section bar portion connecting the island portion, and a lead portion for taking out a semiconductor chip electrode to the outside is fixed, and resin sealing is performed. In the above mold die, a press means is provided corresponding to the section bar portion of the semiconductor device lead frame.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a lead frame and a mold according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of a lead frame of the present invention, a semiconductor device after resin sealing, and a runner portion. In FIG. 1, 1 is a lead frame, 2 is a section bar, 3 is a projection, 4 is a runner, and 12 is a semiconductor device.

According to this configuration, the resin is polymerized and cured in a form in which the protrusions 3 enter the runner portions 4, so that when the mold is opened, the lead frame 1 and the runner portions 4 are not separated, and the runner portions 4 are not separated. Inconveniences that remain in the mold can be eliminated. If the number of the protrusions 3 is one with respect to the runner portion 4, a sufficient effect can be obtained, but the reliability can be improved by further providing a plurality of protrusions 3.
The semiconductor device 12 is finally shipped after the runner portion 4 is removed. Therefore, whether or not the section bar 2 has the protrusion 3 does not affect the quality of the product, and the handling can be exactly the same as the conventional one.

FIG. 2 is a sectional view showing an embodiment of a mold according to the present invention. In FIG. 2A, 1 is a lead frame, 2 is a section bar, 5 is a mold, 6 is an upper mold, 7 is a lower mold, 8 is a runner contact surface, 8
-1 is a protruding protruding blade portion provided on the runner contact surface 8.

The molding die 5 is for sealing the semiconductor chip with resin, and comprises an upper die 6 and a lower die 7. At the time of resin sealing, this upper mold 6 is
As shown in FIG. 2A, the lead frame 1 on which the chip is mounted is mounted on the lower die 7 and the upper die 6 is lowered to fix the lead frame 1 as shown in FIG. 2B. To Then, the protruding blade portion 8-1 provided on the runner contact surface 8 of the upper die 6 presses the section bar 2, and
The projection 3 is automatically formed at a portion corresponding to the runner 4 of the section bar 2. Therefore, when the resin is polymerized and cured in a state where the projections 3 enter the runners 4, the lead frame 1 and the runners 4 are opened when the mold 5 is opened.
However, the inconvenience that the runner part 4 does not separate and the runner part 4 remains in the mold can be removed.

As described above, according to the lead frame of the present invention, since the protrusion is provided at the section bar of the lead frame, the resin for sealing the runner portion is cured including the protrusion, and When the mold is opened, there is no possibility that the resin in the runner portion is left in the mold, and the productivity is improved. According to the mold of the present invention, since the protruding blade portion is provided on the runner contact surface of the upper mold,
The projection can be formed on the section bar portion of the lead frame simultaneously with the resin molding step, and the projection can be formed at low cost without providing a special step.

In the above description, the projection is provided at the section bar portion of the lead frame. Instead of this projection, a plurality of dimples are provided on the section bar, or the section bar portion and the runner portion are connected. Section bar, such as a method of providing a penetrating wire or the like in a brush shape, or providing a small hole in the section bar part so that the resin for sealing the runner part hardens on the upper surface of the section bar through this small hole. Any method can be adopted as long as the method does not separate the runner portion from the runner portion.

[0023]

As described above, according to the first aspect of the present invention, in the lead frame for a semiconductor device, the projecting means is provided on the section bar portion. As described above, the provision of the projecting means on the section bar portion allows the projecting means to bite into the runner portion, and the runner portion is not separated from the lead frame and can be easily taken out of the mold. This can prevent the runner from remaining in the mold and hinder the encapsulation path at the time of encapsulating the next resin, which is effective in improving the yield of the semiconductor device resin encapsulation process.

According to a third aspect of the present invention, in a mold for fixing a semiconductor device lead frame and performing resin sealing, a projection means is provided on a section bar portion of the semiconductor device lead frame. Press means for forming is provided. Since a protruding blade portion, which is a pressing means, is provided on the runner contact surface of the upper mold, a protruding portion can be automatically formed on the section bar of the lead frame simultaneously with the resin molding process, and a special process is provided. The protruding portion can be formed at a low cost without the need.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a lead frame of the present invention, a semiconductor device after resin sealing, and a runner portion.

FIG. 2 is a sectional view showing an embodiment of a mold according to the present invention.

FIG. 3 is a side view showing an example of a conventional general molding apparatus.

FIG. 4 is an explanatory view showing a procedure of a molding step.

FIG. 5 is an explanatory view showing a procedure of a molding step.

FIG. 6 is an explanatory diagram showing a procedure of a molding step.

FIG. 7 is an explanatory view showing a procedure of a molding step.

FIG. 8 is an explanatory view showing a procedure of a molding step.

FIG. 9 is an explanatory view showing a procedure of a molding step.

FIG. 10 is a perspective view showing a state of a resin injected into a mold.

FIG. 11 is a diagram showing a positional relationship among a mold, a semiconductor chip, a runner, and a cavity.

FIG. 12 is a diagram showing a positional relationship among a mold, a semiconductor chip, a runner, and a cavity.

FIG. 13 is an explanatory view showing a problem that a resin remains in a mold at a runner portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lead frame, 2 ... Section bar, 3 ... Projection part, 4 ... Runner part, 5 ... Mold die, 6 ... Upper die,
7: Lower mold, 8: Runner contact surface, 8-1: Protruding protruding blade, 9: Semiconductor chip, 10: Cavity, 11 ...
Pot, 12: semiconductor device, 13: cull, 21: fixed plate, 22: movable plate, 23: hydraulic plunger, 24: guide, 25: chase, 26: heater, 27: high frequency preheater, 28: tablet.

Claims (3)

[Claims] 1. A semiconductor device lead frame comprising an island portion for mounting a semiconductor chip, a section bar portion connecting the island portion, and a lead portion for taking out a semiconductor chip electrode to the outside, wherein a projection means is provided on the section bar portion. A lead frame for a semiconductor device. 2. The semiconductor device lead frame according to claim 1, wherein said projecting means is formed by press working on said section bar portion. 3. A semiconductor device lead frame having an island portion for mounting a semiconductor chip, a section bar portion connecting the island portion, and a lead portion for taking out a semiconductor chip electrode to the outside is fixed to the semiconductor device lead frame. What is claimed is: 1. A molding die for performing resin sealing, comprising: a pressing means corresponding to the section bar portion of the semiconductor device lead frame.