JP2564596B2 - Method for manufacturing semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device manufacturing technique, and more particularly to a technique that is particularly effective when applied to the manufacturing of a semiconductor device using a lead frame.

[Prior Art] Generally, the leads in the lead frame are supported by the lead outer frame via the tie bar, but if the distance from the tie bar to the tip of the inner lead is long, the inner lead bends in various manufacturing processes. It is easy to cause a short between inner leads. Therefore, conventionally, the following manufacturing technique has been considered in order to prevent the bending of the inner lead.

The manufacturing technique will be described below with reference to FIG. 7 and FIG.
Description will be made based on (C).

First, an ordinary lead frame 9 formed by patterning by etching or pressing is prepared, and an insulating tape 2 made of a polyimide resin is attached to the upper surface of the inner lead 1a of the lead frame 9 (FIGS. 7 and 8). (A).

Then, a semiconductor chip 4 is fixed on the tab 3 of the taping lead frame thus obtained by using a bonding material (not shown) such as silver paste as shown in FIG. The bonding pad 4a of the chip 4 and the inner lead 1a are electrically connected by the wire 5 of Au, Al, Cu or the like. Next, the semiconductor chip 4 and its peripheral portion are covered with a sealing resin 6 as shown in FIG. 8 (C). Then, the outer lead 1b is subjected to solder plating to separate the lead 1 in the lead frame 9 from the outer frame of the lead frame and form the outer lead 1b. As a result, a single semiconductor device is obtained.

[Problems to be Solved by the Invention] By the way, in the above manufacturing technique, when the insulating tape 2 is attached, heat treatment must be performed.
The gap between the inner leads 1a after taping changes randomly due to the difference between the coefficient of thermal expansion of the inner leads 1a and the coefficient of thermal expansion of the inner leads 1a, and this change in the intervals of the inner leads 1a causes a decrease in throughput in the manufacturing line. .

That is, in the subsequent wire bonding process, the bonding pad 4a of the semiconductor chip 4 and the inner lead 1a are recognized, and the actual wire bonding is performed based on the recognition result. When the spacing of 1a changes randomly, it is necessary to individually recognize inner leads 1a.
It takes a long time to recognize 1a.

In the taping lead frame used in the above manufacturing technique, the insulating tape 2 is attached to the tip of the inner lead 1a.
Can not be attached. Because inner lead 1a
This is because the tip end of is the connection site of the wire 5. Therefore, conventionally, the insulating tape 2 is attached to a portion retracted from the tip of the inner lead 1a, but in this case, the distance from the tip of the inner lead 1a to the attaching portion of the insulating tape 2 is inevitable. Become longer. Therefore, a slight change in the spacing between the inner leads 1a at the location where the insulating tape 2 is attached causes contact between the tips of the inner leads 1a, causing contact between the inner leads 1a. as a result,
There is a problem that the yield in the semiconductor device manufacturing line is reduced.

Furthermore, in recent semiconductor devices, a large package of a large semiconductor chip 4 in a small package has appeared, but since the length of the inner lead 1a is short in such a semiconductor device, the insulating tape 2 is used. It is not possible to secure a space for attachment inside the resin package, and the above manufacturing technology cannot be used as it is.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method of manufacturing a semiconductor device capable of improving throughput and yield in a manufacturing line.

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.

[Means for Solving the Problems] The outline of the typical inventions among the inventions disclosed in the present application will be described below.

That is, after the insulating tape is attached to the lower surface of the tip end portion of the inner lead of the lead frame formed so as to remain connected to each other when the lead is formed by patterning such as etching or pressing, the inner leads are connected to each other. The tip portion is removed to separate the tip portions from each other, the main surface of the semiconductor chip is partially overlapped with the lower surface of the tip portion of the separated inner lead, and the bonding pad and the inner lead in the semiconductor chip are overlapped with each other in the overlapping portion. Are connected by wires.

[Operation] According to the above-mentioned means, the tip of the connected inner leads is provided with the insulating tape, and then the tip of the inner lead is separated. Therefore, when the insulating tape is attached, the inner lead is attached. The change in the interval is suppressed, and during the manufacturing process,
Due to the effect that the inner lead spacing is appropriately maintained, the recognition time of the inner leads during wire bonding is greatly reduced, and short-circuiting between adjacent wires and between inner leads is prevented. as a result,
The above-mentioned object of improving the throughput and the yield in the manufacturing line is achieved.

In addition, the main surface of the semiconductor chip is partially overlapped with the tip of the inner lead, and the bonding pad and the inner lead of the semiconductor chip are connected by the wire at this overlapping portion, so that the resin package can be downsized. can do.

[Embodiment] An embodiment of a method for manufacturing a semiconductor device according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a first method of manufacturing a semiconductor device according to the present invention.
The lead frame used in this example is shown.

In the figure, reference numeral 11 represents a lead frame formed of 42 alloy or copper alloy or the like, and in this lead frame 11, the tip end portion of the inner lead 12a of the lead 12 is formed by a rectangular connecting portion 13 existing in the central portion. They are interconnected. That is, this lead frame
The 11 is formed by etching, pressing, or the like, and at that time, the tips of the inner leads 12a are formed so as to be connected to each other. The size of the connecting portion 13 is smaller than that of the semiconductor chip 14 to be mounted.

Further, FIG. 2 shows a semiconductor chip 14 fixed to the lead frame 11 shown in FIG.

A bonding pad 14a is formed in the middle area of the main surface of the semiconductor chip 14. In order to realize such a configuration, the layout in the semiconductor chip 14 is changed to, for example, IC
In a semiconductor device such as a memory, although not particularly limited, peripheral circuits such as a sense amplifier and a decoder are arranged in the central portion 41a of the semiconductor chip 14, while a memory array and the like are arranged in the peripheral portion 41b of the semiconductor chip 14. You may do it. Also, for example, in a single-chip microcomputer or the like, although not particularly limited, the CPU core is provided in the central portion 41a of the semiconductor chip 4,
On the other hand, ROM, RAM, I / O, etc. may be arranged in the peripheral portion 41b of the semiconductor chip 4.

Further, in the case of having a large number of bonding pads 14a, the bonding pads 14a may be arranged in a zigzag pattern.

Next, a method of manufacturing the semiconductor device according to the first embodiment using the lead frame 11 will be described.

In this embodiment, the lead frame shown in FIG.
The size of the semiconductor chip 14 (FIG. 3 (D)) to be mounted on the lower surface of the connecting portion 13 and its peripheral portion (tip portion of the inner lead 12a) in 11 (lead frame shown in FIG. 1) is a little or slightly. Attach a large size of insulating tape 15 (Fig. 3 (B)). The insulating tape 15 is not particularly limited, but a tape made of a polyimide resin and having an adhesive attached to the upper surface is used, and the adhesion of the polyimide resin tape is, for example, in an atmosphere of 160 to 200 ° C. 10-20 kg
It is done by applying pressure at / cm ² for 0.3 seconds.

After the insulating tape 15 is attached in this manner, the connecting portion 13 of the lead frame 11 is punched out by using a press as shown in FIG. 3 (C) to separate the tip portion of the inner lead 12a. At this time, a part of the insulating tape 15 attached to the lower surface of the connecting portion 13 is also punched at the same time, but the insulating tape 15 other than the punched portion remains, and the remaining insulating tape 15 remains.
The gap between the inner leads 12a is properly maintained by the 15.

Next, in the die bonding process, the semiconductor chip
The lead frame 11 is placed on the semiconductor chip 14, and a semiconductor chip is formed through a bonding material (not shown) such as silver paste or epoxy resin.
The main surface of 14 is joined to the lower surface of the lead frame 11 (3rd
(Figure (D)). As a method for this, the lead frame 11
The semiconductor chip 14 may be turned upside down and the semiconductor chip 14 turned upside down may be bonded.

Then, in the wire bonding process, the semiconductor chip
Connect the 14 bonding pads 14a and the inner leads 12a to Au, A
It is electrically connected by a wire 16 such as l or Cu (Fig. 3 (E)).

Then, in the resin molding step, the semiconductor chip 14 and its peripheral portion are sealed with the epoxy resin 17 (third part).
(Figure (F)).

Next, after solder plating the outer leads 12b,
The lead 12 is separated from the outer frame of the lead frame 11, and the outer lead 12b is molded.

 As described above, a single semiconductor device is obtained.

According to the method of manufacturing the semiconductor device of the above embodiment, the following effects can be obtained.

That is, according to the method for manufacturing a semiconductor device in the above-described embodiment, the lead frame 11 in which the tips of the inner leads 12a are connected to each other is used, and after the insulating tape 15 is attached, the tips of the inner leads 12a are separated. Because I am trying to
Until the insulating tape 15 is adhered, the connection portion 13 prevents the inner lead 12a from changing its interval, and after the connecting portion 13 is punched out, the insulating tape 15 prevents the inner lead 12a from changing its interval. The distance between the adjacent inner leads 12a is properly maintained, the individual inner leads 12a can be easily recognized during wire bonding, and the wire bonding time can be significantly shortened.

Further, according to the method of manufacturing a semiconductor device according to the above-described embodiment, the main surface of the semiconductor chip 14 is partially overlapped with the lower surface of the tip portion of the inner lead 12a, so that the manufactured semiconductor device is enclosed in a package. Due to the action of increasing the lead length, the lead 12 can be effectively prevented from falling off. In particular, it is effective when enclosing a large semiconductor chip 14 in a small package. Further, since each lead 12 functions as a heat sink, the resistance of the semiconductor device can be reduced, and the characteristics of the semiconductor device can be improved.

In addition, since the main surface of the semiconductor chip 14 is partially overlapped with the lower surface of the tip of the inner lead 12a, the connection between the bonding pad 14a and the inner lead 12a is performed on the upper side of the semiconductor chip 14, so that the resin The package itself can be miniaturized.

Further, according to the method of manufacturing a semiconductor device according to the above-described embodiment, the semiconductor chip 14 is fixed to the lower surface of the tip portion of the inner lead 12a, so that the inner lead 12a is fixed after the semiconductor chip 14 is fixed. With such a function, it is possible to reliably prevent the inner leads 12a and the wires 16 adjacent to each other from coming into contact with each other during resin molding.

With the above synergistic effect, according to the manufacturing method of the present embodiment, it is possible to improve throughput and yield in the semiconductor device manufacturing line, and to provide a highly reliable semiconductor device.

Further, FIGS. 4A to 4F show a second embodiment of the method for manufacturing a semiconductor device according to the present invention.

The lead frame 11 used in this second embodiment is
Lead frame 21 used in the first embodiment (FIG. 1)
The basic configuration is similar to
It differs from the lead frame 11 used in the first embodiment in that the thickness of the tip portion of 22a and the connecting portion 23 is formed to be thinner than the thickness of other lead portions. That is, the lead frame 21 has a recess formed on the lower surface thereof.

In this embodiment, the lead frame shown in FIG.
The insulating tape 15 is attached to the concave portion formed on the lower surface of 21 (FIG. 4 (B)). The other points are substantially the same as those of the first embodiment.

That is, after attaching the insulating tape 15, the lead frame
As shown in FIG. 4 (C), the connecting portion 23 of 21 is punched out using a press to separate the tips of the inner leads 22a, and the semiconductor chip 14 is fixed to the lower surface of the tips of the inner leads 22a (see FIG. 4). (D)), the bonding pad 14a of the semiconductor chip 14 and the inner lead 22a are electrically connected by the wire 16 (FIG. 4 (E)), and the semiconductor chip 14 and its peripheral portion are sealed with the epoxy resin 17. (FIG. 4 (F)). Next, after the outer leads 22b are plated with solder, the leads 22 are separated from the outer frame of the lead frame 21 and the outer leads 22b are molded.

 As described above, a single semiconductor device is obtained.

Also in this embodiment, the same effect as in the first embodiment can be obtained.

Further, according to the method for manufacturing the semiconductor device of this embodiment, the lead frame 21 having the recessed portion on the lower surface as described above is used.
Since the semiconductor chip 14 is fixed to the recess by using the above, the semiconductor chip 14 rises relatively to the lead frame 21 as compared with the first embodiment, and the bonding pad is formed by the relatively short wire 16. 14a and inner lead 2
2a can be connected, and as a result, the occurrence of wire shorts in the resin molding process or the like is suppressed.

The lead frame 21 also has the following advantages.

That is, the distance between the tips of the inner leads 22a becomes smaller as the number of pins increases. Especially, when the tip portion of the inner lead 22a is to be overlapped with the semiconductor chip 14, this tendency is remarkable. However, in this case, the lead frame
If the thickness of 21 is large, the tip portion of the inner lead 22a cannot be accurately patterned. On the other hand, there is a limit to reducing the thickness of the lead frame 21 as a whole. This is because the rigidity of the outer lead 22b is deteriorated and the outer lead 22b is easily bent. On the other hand, according to the lead frame 21 as described above, it is possible to improve the patterning accuracy of the tips of the inner leads 22a without deteriorating the rigidity of the outer leads 22b.

Further, FIGS. 5A to 5F show a third embodiment of the semiconductor device according to the present invention.

In the third embodiment, the lead frame 21 used in the second embodiment (hereinafter referred to as the first lead frame) and the other lead frame 31 shown in FIG.
(Referred to as a lead frame).

Here, on the second lead frame 31, as shown in FIG. 6, a tab 33 supported by its outer frame by a hanging pin 31a.
Only formed. That is, the lead frame 33 is a so-called tab-only lead frame.

Next, a method of this embodiment performed using the lead frames 21 and 31 will be described.

In advance, the back surface of the semiconductor chip 14 is fixed to the top surface of the tab 33 of the second lead frame 31 via a bonding material (not shown) such as silver paste or epoxy resin.

On the other hand, the semiconductor chip 14 mounted on the lower surface of the recess of the first lead frame 21 shown in FIG. 5 (A) (FIG. 5 (D))
Insulation tape 15 that is the same size as or slightly larger than
Is attached (Fig. 5 (B)).

After the insulating tape 15 is attached in this manner, the connecting portion 23 of the first lead frame 21 is punched out by using a press as shown in FIG. 5 (C) to separate the tip portion of the inner lead 22a. The first lead frame 21 is the semiconductor chip
Place it on top of 14 (Fig. 5 (D)). Here, the semiconductor chip 14 may be fixed to the lower surface of the tip portion of the first lead frame 21 as in the first and second embodiments. Next, the bonding pad 14a of the semiconductor chip 14 and the inner lead 22a
Are electrically connected by a wire 16 made of Au, Al, Cu or the like (FIG. 5 (E)).

Then, in the resin molding step, the semiconductor chip 14 and its peripheral portion are sealed with the epoxy resin 17 (FIG. 5 (F)).

Then, after applying solder plating to the outer leads 22b,
The lead 22 is separated from the outer frame of the first lead frame 21, and the outer lead 22b is molded. Second at this stage
The hanging pin 31a of the lead frame 31 is cut. In addition,
When the semiconductor chip 14 is fixed to the inner leads 22a, the suspension pins 31a of the second lead frame 31 may be cut before the resin molding.

 As described above, a single semiconductor device is obtained.

The same effects as those of the second embodiment can be obtained also by the third embodiment.

Further, according to the method of manufacturing a semiconductor device of this embodiment, since the two lead frames are used, the heat dissipation of the manufactured semiconductor device is further increased and the resistance is reduced. Is further improved.

[Effects of the Invention] The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

That is, after attaching the insulating tape to the lower surface of the inner lead end portion of the lead frame in which the inner lead end portions are connected to each other, the inner lead end portions are separated from each other,
Since the main surface of the semiconductor chip is partially overlapped with the lower surface of the tip of the separated inner lead, and the bonding pad and the inner lead of the semiconductor chip are connected by the wire at the overlapping portion, the manufacturing process is performed. The inner lead spacing is properly maintained, the recognition time of the inner leads during wire bonding is greatly reduced, and short-circuiting between adjacent wires and inner leads is prevented. As a result, the above-described object of improving the throughput and the yield in the manufacturing line is achieved.

In addition, since the semiconductor chip is superposed on the tip of the inner lead and the bonding pad and the inner lead of the semiconductor chip are connected by the wire at the overlapping portion, the resin package can be downsized. .

[Brief description of drawings]

FIG. 1 is a plan view showing a part of a lead frame used in a first embodiment of a method for manufacturing a semiconductor device according to the present invention, and FIG. 2 is a semiconductor chip used in a method for manufacturing a semiconductor device according to the present invention. 3A to 3F are process diagrams of the first embodiment of the method for manufacturing a semiconductor device according to the present invention, and FIGS. 4A to 4F are semiconductors according to the present invention. 5A to 5F are process diagrams of a second embodiment of the device manufacturing method, FIGS. 5A to 5F are process diagrams of the third embodiment of the semiconductor device manufacturing method according to the present invention, and FIG. 6 is the present invention. FIG. 8 is a plan view of a second lead frame used in a third embodiment of the method of manufacturing a semiconductor device according to the present invention, FIG. 7 is a plan view showing a part of a lead frame which has been conventionally used, and FIG. 9A to 9C are process diagrams showing a conventional method for manufacturing a semiconductor device. 11,21,31 …… lead frame, 12a, 22a …… inner lead, 13,23 …… connecting part, 14 …… semiconductor chip, 14a …… bonding pad, 15 …… insulating tape.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 61-125059 (JP, A) JP 53-105970 (JP, A) JP 59-92556 (JP, A)

Claims (3)

(57) [Claims] 1. A semiconductor chip is bonded to a lead frame,
When electrically connecting the bonding pad of the semiconductor chip and the inner lead of the lead frame and sealing the semiconductor chip and its peripheral portion with the sealing resin, the inner lead is the tip during lead molding by patterning such as etching or pressing. Using a lead frame molded so as to remain connected to each other in the inner portion, an insulating tape is attached to the lower surface of the tip end portion of the inner lead in this lead frame, and the inner lead interval is held by the insulating tape while the inner tape is held. Removing the interconnected tips of the leads to separate the tips from one another,
The main surface of the semiconductor chip is partially overlapped with the lower surface of the tip of the separated inner lead, and the bonding pad of the semiconductor chip and the inner lead are connected by a wire at the overlapping portion. Manufacturing method of semiconductor device. 2. The semiconductor device according to claim 1, wherein the semiconductor chip is directly fixed to the inner lead at a portion where the inner lead and the semiconductor chip are overlapped with each other. Production method. 3. A lead frame having only tabs supported by tab-hanging pins is used, the back surface of the semiconductor chip is joined to the tabs, and then a part of the main surface of the semiconductor chip is joined. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the tips of the inner leads are overlapped with each other.