JPH07254678A - Lead frame and manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To suppress fluctuation in the molding state of lead frame by providing one frame with more than one row a plurality of regions to be resin sealed and disposing a region, corresponding to the sealing resin supply position of a molding die, between respective rows. CONSTITUTION:A lead frame 1 is provided with two rows of a plurality, e.g. five, of resin sealing regions 1a and a hole 1c for passing a resin 2 from a pot 4 in a molding die 3 to an upper molding die is provided for each row in a region corresponding to the pot 3 of the molding die between the rows. The resin sealing regions 1a of two rows, opposing each other through the pot 4, are arranged symmetrically each other with respect to the center of the hole 1c. When the regions 1a are arranged as mentioned above at the stage of designing a lead frame, the number of lead frames being set for the molding die can be halved in multi-pot molding system and thereby fluctuation in the resin flush due to the difference of plate thickness can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of manufacturing semiconductor devices, and is particularly effective when applied to packaging technology for sealing a semiconductor chip mounting region.

[0002]

2. Description of the Related Art The conventional mold (resin sealing) method is 8
~ 16 lead frames are set in a large mold and the resin (sealing resin) put in the pot in the center of the mold is extruded by a plunger, and long flow paths (cull, runner, gate) It was a transfer mold method (semi-automatic) in which each cavity is filled by passing through, but in recent years, as shown in FIG.
Multiple pots are set in a mold so as to be sandwiched, and a transition is made from the multiple pots to a multi-pot mold method (automatic) in which each cavity is filled with resin by passing through a short flow path consisting of cull, runner, and gate. .

Most lead frames are made up of about 6 ICs arranged in a line in one frame.
There is also used one frame having two or more rows (multi-row multi-row). When molding is performed using this lead frame 16, as shown in FIG. 8, two lead frames 17 are arranged on a mold 18 so as to sandwich the row of pots, and clamped by the upper mold. At the time of injecting the resin, as shown in FIG.
h, the first runner 18e, and the gate 18g
The second runner 18 after being injected into the cavity 18c of
a second cavity that passes through f and is juxtaposed with the first cavity 18c.
Is injected into the cavity 18d.

Regarding the molding apparatus, for example,
"Electronic Materials Separate Volume VLSI Manufacturing / Testing Equipment Guidebook 1988 Edition" (published by the Industrial Research Institute), pages 138 to 145, etc.

[0005]

In the molding method in which a plurality of lead frames are placed in a mold while sandwiching the pot as described above, the resin flash in each lead frame is different due to the difference in the plate thickness of each lead frame. There is a difference in the level of (the resin enters and spreads between the lead frame and the mold holding it). In order to eliminate the difference, the mold needs to have an elastic structure, which makes the mold structure complicated and expensive.

In terms of the lead frame setting mechanism, when a plurality of lead frames are placed in a mold by sandwiching the pot, one pot is sandwiched and one lead frame is rotated by 180 ° so that the gates face each other. Since it is necessary to arrange each lead frame symmetrically with respect to the center of the pot, the lead frame setting mechanism is complicated.

In the transportation in the apparatus, as shown in FIG. 7, after molding, the two lead frames 13 are connected to the cull portion 14c and the runner portion 14b only by the gate portion 14d. The transport mechanism is very complicated in order to prevent the falling. Further, in the gate break (separation of the resin sealing body at the gate portion), the thinnest (thin) gate portion is broken by applying a force to the cull portion.
Due to differences in the lead frame, resin flow path shape, resin material, etc., there are differences in gate breakability such as remaining gates, frame deformation, etc., making uniform gate breaks difficult.

In the case of the conventional molding method using a multi-row, multi-row lead frame, one-shot molding
It is difficult to keep the molding conditions of all cavities the same and perform uniform filling. That is, when a multi-row, multi-row lead frame is used, as shown in FIG. 9, the resin 17 moves from the first cavity 18c to the second cavity 18c.
Since the viscosity increases while flowing into the cavity 18d, the fluidity of the resin 17 is different, and the resin injected into the second cavity 18d has a large viscosity.
Since the chip mount portion of the lead frame 16 is pushed down (raised) from the rear surface direction, the upper and lower resin thicknesses are unbalanced, and if the resin is filled as it is, as a result, the bonding pads and inner leads of the semiconductor chip 16a There arises a problem that the wire 16b connecting the wires is exposed from the resin sealing body.

The present inventor diligently paid attention to the fact that the above-mentioned problem occurs due to the positional relationship that the pot is located between the two lead frames in the mold.

Therefore, an object of the present invention is to reduce variations in the molding state of the lead frame in the multi-pot molding method.

Another object of the present invention is to make the gate breaks uniform in the multi-pot mold method.

Another object of the present invention is to simplify the carrying mechanism and the setting mechanism in the multi-pot molding apparatus.

Another object of the present invention is to make the molding conditions of the multi-row, multi-row lead frame uniform in the multi-pot molding method.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0015]

The outline of the representative one of the inventions disclosed in the present application will be briefly described as follows. That is, two or more rows in which a plurality of regions to be resin-sealed are provided in one frame, and the resin for molding the resin-sealing die is provided between the rows of the regions to be resin-sealed. An area corresponding to the supply position is provided.

[0016]

According to the above-mentioned means, the conventional two lead frames are arranged so as to sandwich the pot position to form one frame. Therefore, the number of lead frames set in the mold is reduced by half and the resin due to the difference in plate thickness is used. Flash variations can be reduced. Further, since the gate break can be performed with a cutting die, the gate break of each sealing body can be performed uniformly. Furthermore, after the molding, the resin cured in the resin flow path is fixed on one lead frame, so that a mechanism for preventing the resin from falling inside the apparatus is not required, and the transport mechanism can be simplified. Further, since the mold areas on both sides can be set to be point-symmetrical on the lead frame with the pot position of the lead frame as a symmetry point, a mechanism for rotating the lead frame in the device is not required and the lead frame setting mechanism can be simplified. . Further, since the pot position is provided between the rows, the resin can be injected under uniform conditions without causing a difference in the viscosity of the resin between the cavities when the resin is injected.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which one embodiment of the present invention is applied to a double lead frame will be described below.

FIG. 1A shows a lead frame 1 of the present invention.
2B is a partial cross-sectional view showing a molded state of the lead frame 1 set in the mold 3. FIG.
In the partial plan view of (a), before and after molding are separated by a one-dot chain line, the upper part shows after molding, and the lower part shows before molding.

The lead frame 1 is provided with two rows of a plurality of resin sealing areas 1a, for example, five rows, and the pot of the mold 3 is provided between the rows of the resin sealing areas 1a. In a region corresponding to (resin (sealing resin) supply position), holes 1c for passing the resin 2 from the pot 4 provided in the mold 3 to the upper mold are provided for each station. The resin sealing regions 1a in each of the two rows facing each other with the pot 4 in between are arranged in a point-symmetrical relationship with the center of the hole 1c as the point of symmetry. By arranging such an arrangement at the stage of designing the lead frame, it is not necessary to use a mechanism in which one of the two lead frames is conventionally rotated by 180 ° when the two lead frames are arranged by sandwiching the pot. Therefore, the lead frame setting mechanism can be simplified.

The mold 3 is composed of an upper mold 3a and a lower mold 3b. With these, a cavity 3c forming the sealing body 2a, a runner 3d serving as a flow path for the molten resin 2, a gate 3e, and a cull 3f are formed. Form. The pot 4 is provided between the cavities in the row direction of the lower mold 3b.

Hereinafter, a method of assembling the semiconductor device using the lead frame 1 will be described.

First, the semiconductor chip is attached to the lead frame 1
After mounting on the respective resin-sealed regions 1a and connecting the electrode pads and the inner leads by wire bonding or the like, they are set on the lower mold 3b of the mold 3 as shown in FIG. At this time, the hole 1c of the lead frame 1
The lead frame 1 is aligned with the pot 4 of FIG.
And is clamped by the upper mold 3a. In addition, mold 3
Is heated to a temperature at which the resin melts. Next, put a tablet in which the resin is formed into a cylindrical shape into the pot 4,
By raising the tablet with the plunger 5,
The resin 2 is injected into the cavity 3c. Resin 2 is
What is melted and liquefied by coming into contact with the inner wall of the mold 3 such as the cull 3f flows through the runner 3d and the gate 3e and is injected into the cavity 3c. Cavity 3c
The resin 2 filled inside is then heat-cured, and the sealing body 2
While a is formed, the resin on the flow path such as the cull 3f, the runner 3d, the gate 3e, etc. is also thermoset, and the gate portion 2b, the runner portion 2c, and the cull portion 2d are fixed to the lead frame 1 as they are. Molded lead frame 1
Bake to completely cure the mold resin. After that, the cull portion 2d, the runner portion 2c, the gate portion 2b
The lead frame 1 on which the resin on the flow path remains, is set in the cutting mold, and the sealing body 2a, that is, the semiconductor device is separated from the lead frame 1 individually. that time,
A metal part such as an outer lead is cut and separated from the frame part 1b, and the sealing body 2a made of a resin is cut and separated from the cull part 2d and the runner part 2c by the cutting mold at the gate part 2b. This allows a uniform gate break. The outer lead of the sealing body 2a cut and separated from the lead frame 1 is formed into a predetermined shape.

3 and 4 are modifications of the shape of the hole of the lead frame through which the resin passes. In FIG. 3, a plurality of pinholes 6 a are provided in the pot-corresponding region of the lead frame 6. By providing the pinhole 6a, when the resin 2 pushed out by the plunger 5 passes through the pinhole 6a, the pressure applied to the resin 2 becomes large, so that the air trapped in the resin 2 is crushed. Therefore, problems such as bulging of the package appearance due to voids and abnormal bending of the gold wire can be reduced. As described above, by making the resin passage hole narrower than the cross-sectional area of the pot, any shape may be used as long as it has the above-mentioned action, for example, a cross-shaped slit 7a shown in FIG. But good.

In FIG. 5, the runner 9d and the gate 9e are the lower mold 9
It is a figure which shows the method of molding the lead frame of this invention with the metal mold | die 9 provided in b. In this case, the lead frame 8 provided with no hole or slit through which the resin passes is used, and the portion corresponding to the pot 10 is brought into close contact with the upper mold 9a for molding.

When the pot-corresponding portions of the lead frames 6, 7, and 8 shown in FIGS. 3, 4, and 5 are to be cut and removed before the individual sealing bodies are separated, the pots are placed in the respective portions. By providing the shape notch, the removability is improved.

The effects of the present invention will be described below.

Since two conventional lead frames are arranged so as to sandwich the pot position, one frame is provided.
The number of lead frames set in the mold is halved, and variations in resin flash due to differences in plate thickness can be reduced.
Further, since the gate break can be performed with a cutting die, the gate break of each sealing body can be performed uniformly. Furthermore,
After the molding, the resin cured in the resin flow channel is fixed on one lead frame, so that a mechanism for preventing the resin from falling inside the apparatus is not required, and the transport mechanism can be simplified.
Further, since the mold areas on both sides can be set to be point-symmetrical on the lead frame with the pot position of the lead frame as a symmetry point, a mechanism for rotating the lead frame in the device is not required and the lead frame setting mechanism can be simplified. . Further, since the pot position is provided between the rows, the resin can be injected under uniform conditions without causing a difference in the viscosity of the resin between the cavities when the resin is injected.

(1) Since two conventional lead frames are arranged so as to sandwich the pot position to form one frame, the number of lead frames set in the mold is reduced by half, and the resin flash due to the difference in plate thickness is eliminated. Variation can be reduced.

(2) Since the gate break can be performed with a cutting die, the gate break of each sealing body can be performed uniformly.

(3) After the molding, the resin cured in the resin flow path, that is, the cull portion, the runner portion, and the gate portion are fixed on one lead frame, so that the resin is conveyed to the cutting die. , Partial drop does not occur. Therefore, the mechanism for preventing the resin from falling inside the apparatus is not required, and the transport mechanism can be simplified.

(4) Since the resin sealing regions on both sides can be arranged point-symmetrically with respect to one lead frame with the pot position of the lead frame as a symmetry point, a mechanism for rotating the lead frame is not required and the lead frame set The mechanism can be simplified.

(5) Since the pot position is provided between the rows, the resin can be injected under uniform conditions without causing a difference in the viscosity of the resin between the cavities. .

The invention made by the inventor of the present invention has been specifically described based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. For example, in the above embodiment, one pot is set for each series of lead frames, but as shown in FIG. 6, even if one pot is provided for every two series, the same effect as above can be obtained. Also, if the lead pitch is small and the number of leads is small, there is not much difference in the fluidity of the resin even with the conventional multi-row multiple lead frame, so two pots are separated by one pot position. Also, molding can be performed without problems.

As described above, the lead frame of the present invention is
Various problems in the multi-pot mold method can be easily solved.

[0035]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, in a lead frame in which two or more rows of a plurality of regions to be resin-sealed are provided in one frame, resin-sealing is provided between the columns of the regions to be resin-sealed. By providing a region corresponding to the mold sealing resin supply position, resin injection conditions are made uniform, resin flash variations are reduced, gate breaks are made uniform, and the device transport mechanism and lead frame setting mechanism are simplified. Can be achieved.

[0037]

[Brief description of drawings]

FIG. 1A is a partial plan view of a lead frame of the present invention before and after molding. (B) is a partial cross-sectional view showing a molded state of the lead frame set in the mold.

FIG. 2 is a view showing a state in which the lead frame of the present invention is placed in a mold.

FIG. 3 is a view showing a state in which a lead frame of the present invention is provided with a pinhole through which a resin passes.

FIG. 4 is a diagram showing a lead frame of the present invention in which a slit through which a resin passes is provided.

FIG. 5 is a diagram showing a method of molding the lead frame of the present invention with a mold 9 provided with a runner 9d and a gate 9e on a lower mold 9b.

FIG. 6 is a view showing a case where the position of the hole through which the resin of the lead frame of the present invention passes is changed.

FIG. 7 is a diagram showing an arrangement of a conventional multiple-row single-row lead frame in a mold.

FIG. 8 is a diagram showing an arrangement of a conventional multiple row lead frame in a mold.

FIG. 9 is a view showing a mold state of a conventional multiple row lead frame in a mold.

[Explanation of symbols]

1 ... Lead frame, 1a ... Resin sealing area, 1b ...
… Frame, 1c… Hall, 2… Resin, 2a…
... Sealing body, 2b ... Gate part, 2c ... Runner part, 2d
...... Cal part, 3 ... Mold, 3a ... Upper mold, 3b ... Lower mold, 3c ... Cavity, 3d ... Runner, 3e ... Gate, 3f ... Cull, 4 ... Pot, 4a ... … Pot shape, 5 …… Plunger, 6 …… Lead frame, 6a…
... pinhole, 7 ... lead frame, 7a ... slit, 8 ... lead frame, 9 ... mold, 9a ... upper mold, 9b ... lower mold, 9c ... cavity, 9d ... runner, 9e ... gate, 10 ... pot, 11 ... plunger, 12 ... lead frame, 12a ... resin sealing region, 12b ... frame part, 12c ... hole, 12d
...... Runner part, 13 ...... Lead frame, 14a ...... Encapsulation body, 14b ...... Runner part, 14c ...... Cull part, 14d
...... Gate part, 15 …… mold, 16 …… lead frame, 16a …… semiconductor chip, 16b …… wire, 17
...... Resin, 17a ...... Sealing body, 17b ...... First runner part, 17c ...... Second runner part, 17d ...... Cull part,
18 ... Mold, 18a ... Upper mold, 18b ... Lower mold, 18
c ... 1st cavity, 18d ... 2nd cavity, 18e ... 1st runner, 18f ... 2nd runner, 18g ... Gate, 18h ... Cal, 19 ... Pot, 20 ... Plunger,

Claims (4)

[Claims] 1. A lead frame in which two or more rows in which a plurality of regions to be resin-sealed are arranged in one frame are provided, and between the columns of the regions to be resin-sealed, A lead frame, wherein a region corresponding to a sealing resin supply position of a resin sealing die is provided. 2. A hole or slit for allowing the sealing resin to pass from one surface of the lead frame to the other surface is provided in a region corresponding to the sealing resin supply position of the resin sealing mold. The lead frame according to claim 1, wherein: 3. A method of manufacturing a semiconductor device using a lead frame, wherein one frame comprises two or more rows in which a plurality of regions to be resin-sealed are provided, wherein the lead frame is made of resin. A lead frame having a region corresponding to the sealing resin supply position of the resin sealing mold is provided between the columns of the regions to be stopped, and (a) the region to be sealed with the resin is sealed. A semiconductor chip is mounted on the resin-sealing area in a resin-sealing mold provided with a cavity, a gate, and a cavity through which the sealing resin flows, and a cavity corresponding to the resin-sealing area. A step of setting the lead frame and injecting a sealing resin into the cavities on both sides from a region corresponding to a sealing resin supply position of a resin sealing mold to perform resin sealing; Cal, the runner and the gate cure And a step of cutting and removing the sealing resin remaining on the lead frame and the portion of the lead frame other than the leads for external extraction by using a cutting die to separate the individual semiconductor devices. A method of manufacturing a semiconductor device, comprising: 4. The lead frame passes the sealing resin from one surface of the lead frame to the other surface in a region corresponding to a sealing resin supply position of the resin sealing mold. 4. The method of manufacturing a semiconductor device according to claim 3, wherein a lead frame provided with holes or slits is used.