JPH08330463A - Manufacture of ball grid array type semiconductor device - Google Patents

Abstract

PURPOSE: To shorten the time required for boring of a hole for fusing and connecting a solder ball to an inner lead, and reduce the manufacture cost of a semiconductor device with a boring means which is not worn away. CONSTITUTION: Out of molds for injection molding of resin, the lower mold 7 is one where a specified number of projections 12 for formation of small holes 10 for connection of solder balls are arranged at the face for formation of cavities, and resin is injected into this mold, so small holes for solder balls 11 connected to an inner lead 4 are made, in vertical direction to the inner lead 4, at the bottom of a package after injection of resin, and resin burrs 13 are produced at the same time at the bottoms of the tips of these small holes 10. The method of removing these resin burrs is performed as follows. The thin resin burrs are removed by applying a laser beam 14 to it or injecting the jet water by high-pressure water jet from small bores for removal with hydraulic pressure, and then the electric connection between the inner lead and the solder ball is performed, so extremely high-speed processing work can be performed, and it is effective for reduction of manufacture cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ball grid array type semiconductor device, and more particularly to a method for manufacturing a ball grid array type semiconductor device in which a small hole for mounting solder balls is improved.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have come to be used in a wide range of fields including industrial equipment and consumer equipment, as the degree of integration has improved. For this reason, a semiconductor device having a package having a shape that is easy to use for each device such as miniaturization, thinning, low cost, and multi-pin has been commercialized.

One of the package forms of these semiconductor devices is a ball grid array type semiconductor device. An example of this type of semiconductor device is Japanese Patent Laid-Open No. 61-7.
No. 3353. Referring to FIG. 2, which is a sectional view of the semiconductor device described in the publication, a semiconductor chip 1
Is mounted on the island 2, and its electrodes are wire-bonded to the inner leads 4 with the fine metal wires 3. The outer leads of the lead frame are cut into plastic packages 16 at the time of manufacture so as not to go out of the package. Only the inner leads 4 are left in the package 16, and holes (small holes) communicating with the inner leads 4 are formed on the bottom surface of the package 16 in order to establish conduction between the inner leads 4 inside the package 16 and the conductor pattern of the external board 17. ) 10 was drilled and this small hall 1
The solder 11 is attached to the wire 0.

An outline of a method for drilling small holes for solder balls in a conventional ball grid array type semiconductor device of this kind is shown in FIG. 2A and a sectional view showing a bottom view of the resin-sealed semiconductor device. Referring to FIG. 2 (c), while the punching device is horizontally scanned with respect to a predetermined position on the bottom surface side corresponding to a predetermined inner lead, Small diameter drill 1
The holes are pierced one by one using No. 8.

The depth of the small hole 10 to be drilled is so deep that it reaches the back surface of the inner lead 4.

[0006]

In the above-mentioned conventional method of manufacturing a ball grid type semiconductor device, a small hole for melting and connecting a solder ball to an inner lead is formed on the bottom side of the semiconductor device by using an extremely small diameter drill. In order to perforate the resin, the perforation time required a long time of about 0.8 seconds per hole.

For example, when measuring the time in the case of a 208-hole specification of a typical ball grid array type semiconductor device, it takes about 3 minutes to pierce one device, and mass production leads to low cost. The required semiconductor device has a disadvantage that the manufacturing cost is increased.

Further, since the encapsulating resin of the semiconductor device contains a component of silica or epoxy resin, the workability of the drill is poor and the cutting edge of the drill causes pitching and wear.

As a result, the hole is broken by drilling about 1000 holes, and therefore the cutting edge of the drill must be frequently replaced, and the processing tool cost is about 80 yen per semiconductor device at present, and the manufacturing cost is further increased. It had the drawback of becoming one of the factors of the soaring price.

The object of the present invention has been made in view of the above-mentioned drawbacks, and shortens the time for drilling holes for melting and connecting solder balls to inner leads, and uses a piercing means which does not wear to manufacture semiconductors. It is an object of the present invention to provide a method of manufacturing a ball grid array type semiconductor device which is intended to reduce the cost.

[0011]

A feature of the ball grid array type semiconductor device of the present invention is that a semiconductor chip is mounted on an island of a lead frame, and its electrodes and inner leads are wire-bonded with a thin metal wire. The mold is sandwiched and clamped between an upper mold and a lower mold having a cavity portion corresponding to a shape, and a resin flows into the cavity from a gate provided at one end of the cavity of the upper mold to be filled. A resin-sealed semiconductor device in which small holes are provided from the lower surface of the semiconductor device to the back surface of each of the inner leads, and solder balls connected to the inner leads in these small holes. In the method for manufacturing a ball grid array type semiconductor device in which the small holes are formed, the arrangement of the small holes includes forming the cavity. Instead of the lower mold, using a lower mold in which projections corresponding to the small holes are provided on the surface thereof, and allowing the resin to flow into the cavity, the inner lead is formed by the inflow pressure. The small holes each having a thin resin burr formed between the back surface of the inner lead and the bottom of the small hole are respectively provided by pressing the small holes against the tips of the protrusions.

Further, after the thin resin burr formed on the bottom of the small hole of the semiconductor device shaped into the predetermined shape is removed by burning out by irradiating a laser beam, the inner lead and the solder ball are removed. Can be electrically connected.

Further, instead of the laser light irradiation,
It is also possible to inject jet water by a high-pressure water jet having a predetermined small diameter and remove the thin resin burr by the water pressure.

[0014]

First, an embodiment of the present invention will be described with reference to the drawings. 1A is a step for explaining a method of manufacturing a ball grid array type semiconductor device of the present invention, which is a cross-sectional view of the semiconductor device at the time of resin injection, and FIG. 1B is formed at the bottom of the hole. FIG. 1C is a cross-sectional view of the semiconductor device in the thin resin burr removal step performed, and FIG. 1C is a cross-sectional view of the semiconductor device in a state in which solder balls are melt-connected.

Referring to FIGS. 1A to 1C, in this method of manufacturing a semiconductor device, a semiconductor chip 1 is mounted on an island 2 of a lead frame, and its electrode is wire-bonded to an inner lead 4 with a thin metal wire 3. Later, an upper mold 6 having a cavity 5 adapted to a predetermined package shape
And a lower mold 7 to clamp the mold, and in a sealing step, a resin 9 flows into the cavity from a gate 8 provided at one end of the cavity 5 of the upper mold 6 to fill the cavity. A small hole 10 reaching the back surface of each of the inner leads 4 from the lower surface of the semiconductor device.
A solder ball 11 connected to the inner lead 4 is formed at 0. To describe the method of the present invention more specifically, the arrangement of the small holes 10 is performed by lowering the lower molds each having the projections 12 corresponding to the small holes on the surface of the lower mold 7 forming the cavity 5. The resin 9 is used to flow into the cavity 5.

This resin is a thermosetting resin. For example, epoxy pellets (E pellets), which are a known technique, are sealed with a low-pressure transfer molding method. That is, in the resin encapsulation, the lead frame on which the semiconductor chip 1 is mounted is set by being sandwiched between the upper mold 6 and the lower mold 7 of the package heated to a high temperature of 150 ° to 180 ° C.
The mold is clamped by a mold press, and a thermoplastic resin having fluidity is injected into the mold at a low pressure of 60 to 120 kg / cm ² to transfer-mold the package.

Due to the injection pressure, the resin flow flows above the lead frame in the resin inflow passage, and flows from the gap between the inner leads 4 or the gap between the inner leads 4 and the island 2 into the cavity 5 on the lower surface of the lead frame. Is also filled.

The resin 9 that has flowed into the cavity 5 exerts a force in a direction in which the inner lead 4 of the lead frame is pushed down into the lower mold 6 by the injection pressure. The resin 9 injected at this time flows in the direction shown by the arrow in the figure, and slightly enters between the inner lead 4 and the tip of the protrusion 12.

Thereafter, the mold 9 is held in a clamped state until the curing of the resin 9 is completed.
Opens and the resin-sealed package is removed from the mold. The small holes 10 are respectively opened by the projections 12 from the lower surface of the resin-sealed package toward the bottom surface of the inner leads 4.

The positions where these holes 10 are opened, that is, the positions of the projections 12 of the lower mold 7 may be, for example, any positions where one hole is opened perpendicularly to one inner lead. In order to dispose the leads 11 at equal intervals and at equal pitches, it is appropriate that the inner leads be lead frames arranged in parallel at equal intervals.

It is sufficient that these small holes 10 have the same size (diameter) as a lead mounting hole for a resistor or the like on a normal printed circuit board.

In the above-described method for opening the small holes 10 by the lower mold 7 in the resin knotting step, the opened small holes 1
At the bottom of 0, there is a thin resin burr 1 between the inner lead 4
3 is formed, it is necessary to remove it.
That is, the solder ball 11 is formed by the thin resin burr 13.
This is because electrical connection between the power supply and the leaner lead 4 cannot be made.

In order to remove this thin resin burr 13,
The resin burr 13 is burned off by irradiation with a laser beam 14.
The laser beam 14 is effective because it can be processed at an extremely high speed. For example, in the case of a 208-hole specification of a ball grid array type semiconductor device, it can be processed in about 1.5 seconds per semiconductor device, so that one small hole is required. It is 0.007 seconds per hit, and a factory with a processing efficiency of about 100 times compared to the case of drilling can be made.

Next, after the solder balls 11 are arranged in the small holes 10 by a known technique, a solder ball method, the solder balls 11 are heated in an infrared reflow furnace, and the solder balls 11 and the inner leads 4 are melted and connected to each other. Make a proper connection.

By this bonding, the electrical connection of the input / output signal lines of the semiconductor chip 1 is connected via the electrode group for input / output signals, the thin metal wires 3 and the solder balls 11.

The lead frame of the package to which the solder balls 11 are bonded is cut and separated along the side surface at the place where the respective outer leads protrude from the side surface of the package to the outside in a molding step, to become individual packages.

The package having the solder ball group formed as described above is mounted on an LSI test apparatus using these solder balls 11, and the electrical characteristics test of the mounted semiconductor chip 1 is performed. Good products are sorted by

Although the present embodiment has been described using the laser beam 14 to remove the thin resin burr 13,
It is not necessary to use a laser beam, and high-pressure water jet water can be sprayed onto the resin burr to remove the water. In that case, the jet pressure of jet water is 100kg / c.
m ² and, in the case of the 208-hole specification of the ball grid array type semiconductor device as in the above example, since it is possible to process about 30 seconds per semiconductor device, it is 0.144 seconds per one small hole. Although it is naturally inferior to the laser irradiation, the processing efficiency can be improved about 6 times as compared with the case of drilling.

[0029]

As described above, the method of manufacturing a ball grid array type semiconductor device according to the present invention provides a small hole for connecting a solder ball to a cavity forming surface of a lower die among resin injection molding dies. It has a mold in which a predetermined number of protrusions for forming the resin are formed, and the resin is sealed using this mold. A small hole is formed perpendicularly to the inner lead, and a thin resin burr is also formed between the small hole and the inner lead on the bottom surface of the tip of the small hole. Or remove the thin resin burrs by injecting water with a high-pressure water jet having a predetermined small diameter, and then remove the inner lead and solder board. Because of making electrical connection, it is extremely fast processing operations. Therefore, this is an effective method for reducing the manufacturing cost.

[Brief description of drawings]

FIG. 1 (a) is a step for explaining the method for manufacturing a ball grid array type semiconductor device of the present invention, and is a cross-sectional view during resin injection. (B) It is sectional drawing of the semiconductor device of the thin resin burr removal process formed in the hole bottom part. (C) is an electrogram showing a state in which the solder balls are fusion-connected.

FIG. 2 is a cross-sectional view showing an example of a conventional ball grid array type semiconductor device.

FIG. 3A is a bottom view of a main part of a resin-sealed semiconductor device for explaining a method of forming a hole for a solder ball. (B) It is sectional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Island 3 Fine metal wire 4 Inner lead 5 Cavity part 6 Upper die 7 Lower die 8 Gate 9 Resin 10 Small hole 11 Solder ball 12 Protrusion part 13 Thin resin burr 14 Laser beam 16 Package 17 Resin substrate 18 Drill

Claims (3)

[Claims] 1. A semiconductor chip is mounted on an island of a lead frame and its electrodes and inner leads are wire-bonded with a thin metal wire, and then sandwiched between an upper mold and a lower mold having a cavity portion conforming to a predetermined package shape. A resin-sealed semiconductor device in which a resin is flowed into the interior of the cavity from a gate provided at one end of the cavity of the upper mold, and is filled and sealed with a resin. A method for manufacturing a ball grid array type semiconductor device, comprising: arranging small holes reaching the back surface of each inner lead from the lower surface of the device, and forming solder balls connected to the inner leads in these small holes. In the arrangement, a projection corresponding to the small hole is provided on the surface of the lower mold forming the cavity instead of the lower mold. Using the lower molds respectively disposed, the resin is caused to flow into the cavity, and the inner leads are pressed against the tips of the protrusions by the inflow pressure, whereby the inner lead back surface and the small holes are pressed. A method of manufacturing a ball grid array type semiconductor device, wherein the small holes each having a thin resin burr formed between the bottom and the bottom are provided. 2. The inner lead and the solder ball are removed after the thin resin burr formed on the bottom of the small hole of the semiconductor device shaped into the predetermined shape is burned and removed by irradiating with laser light. 2. The method for manufacturing a ball grid array type semiconductor device according to claim 1, wherein the electrical connection is performed. 3. The method according to claim 2, wherein instead of the laser beam irradiation, water jet is injected by a high-pressure water jet having a predetermined small diameter, and the thin resin burr is removed by the water pressure.
The manufacturing method of the ball grid array type semiconductor device described in the above.