JP3507819B2 - Resin-sealed semiconductor device and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a resin-sealed semiconductor device in which a semiconductor chip and signal connection leads connected to the semiconductor chip are sealed with a sealing resin, and a resin-sealed semiconductor device. The present invention relates to a lead frame suitable for manufacturing, and particularly to improvement of a thinned one.

[0002]

2. Description of the Related Art In recent years, in order to cope with miniaturization of electronic equipment, it has been required to mount semiconductor parts mounted on the electronic equipment at a high density, and accordingly, the miniaturization and thinning of semiconductor parts have been advanced. I'm out.

A conventional resin-sealed semiconductor device will be described below.

FIG. 20 is a sectional view of a conventional resin-sealed semiconductor device. As shown in FIG. 20, the conventional resin-encapsulated semiconductor device is a resin-encapsulated semiconductor device of a type having external electrodes on the back surface side.

The conventional resin-encapsulated semiconductor device includes an inner lead 101, a die pad 102, and a lead frame including a suspension lead (not shown) that supports the die pad 102. And the die pad 10
The semiconductor chip 104 is bonded to the upper surface of the semiconductor chip 104 by an adhesive, and the electrode pads (not shown) of the semiconductor chip 104 and the inner leads 101 are electrically connected by the thin metal wires 105. The die pad 102, the semiconductor chip 104, a part of the inner lead 101, the suspension lead and the thin metal wire 105 are sealed with a sealing resin 106. In this structure, the sealing resin 106 does not exist on the back surface side of the inner lead 101.
The back surface side of is exposed, and the lower portion of the inner lead 101 including this exposed surface is the external electrode 107. In order to secure the adhesion with the sealing resin 106, the side surfaces of the inner lead 101 and the die pad 102 are not orthogonal to the front and back surfaces, but are tapered so as to expand upward. .

In such a resin-sealed semiconductor device, the back surface of the sealing resin 106 and the back surface of the die pad 102 are on a common surface. That is, since the back surface side of the lead frame is not substantially sealed, a thin resin-sealed semiconductor device is realized.

In the manufacturing process of the resin-sealed semiconductor device having the structure shown in FIG. 20, first, the inner lead 1
01, a lead frame having the die pad 102 is prepared, and mechanical or chemical processing is performed to make the side surface of the lead frame tapered. Next, after the semiconductor chip 104 is bonded onto the die pad 102 of the prepared lead frame with an adhesive, the semiconductor chip 104 and the inner lead 101 are electrically connected by the fine metal wire 105. The fine metal wires 105 include fine aluminum wires and gold (A
u) line etc. are used suitably. Next, the die pad 10
2. The semiconductor chip 104, the inner lead 101, the suspension lead and the thin metal wire 105 are sealed with the sealing resin 106. In this case, the lead frame to which the semiconductor chip 104 is joined is housed in the sealing mold and transfer-molded. Especially, the back surface of the lead frame comes into contact with the upper mold or the lower mold of the sealing mold. In this state, resin sealing is performed. Finally, the outer leads protruding outward from the sealing resin 106 after resin sealing are cut to complete the resin-sealed semiconductor device.

[0008]

However, although the above-mentioned conventional resin-encapsulated semiconductor device can be made thinner, it has the following problems.

First, the sealing resin exists on the upper surface and the side surfaces of the die pad, but the sealing resin does not exist on the back surface side of the die pad. Therefore, there is a problem that the holding force of the sealing resin on the die pad and the semiconductor chip is reduced, and the reliability is deteriorated.

Secondly, there are problems that the semiconductor chip is adversely affected by the stress of the sealing resin and the stress after mounting, or cracks occur in the sealing resin. In particular, when moisture penetrates between the die pad and the sealing resin, the adhesiveness between them and the cracking become remarkable. As a result, there is a problem that reliability is further deteriorated.

Thirdly, in general, when mounting a resin-sealed semiconductor device on a mounting board, the resin-sealed semiconductor device is mounted on the mounting board by self-alignment using the tension of solder. You can set the position accurately,
There is room for improvement in the work time and mounting position accuracy by shortening the time required for self-alignment to stabilize.

Fourth, when a mounting substrate and a die pad are joined, if a part of the sealing resin protrudes on the back surface of the die pad and a so-called resin burr intervenes, contact with the heat radiation pad or the like becomes insufficient, and the heat radiation characteristics There is a possibility that desired characteristics such as the above cannot be sufficiently exhibited. On the other hand, this resin burr can be removed by using a water jet or the like, but such a treatment requires complicated labor, and the nickel, palladium, and gold plating layers are peeled off by the water jet process, and impurities are attached. However, it is necessary to plate the portion exposed from the resin encapsulation after the resin encapsulation step, which may lead to a reduction in work efficiency and a deterioration in reliability.

The present invention has been made in view of the above points, and has the following objects.

A first object of the present invention is to provide a resin-sealed semiconductor device having a high cell alignment function on a mounting substrate and a method for manufacturing the same.

[0015]

A resin-sealed semiconductor device according to the present invention includes a semiconductor chip having electrode pads, a die pad for supporting the semiconductor chip, signal connecting leads, and electrode pads of the semiconductor chip. At least a part of the lower portion of the die pad, which includes a connecting member that electrically connects the signal connecting lead, a die pad, the semiconductor chip, a sealing resin that seals the signal connecting lead, and the connecting member. At least a part of the lower portion of the signal connecting lead is exposed from the sealing resin, and the lower surface of the exposed portion of the die pad and the lower surface of the exposed portion of the signal connecting lead are The height positions are different from each other.

As a result, when the resin-sealed semiconductor device is mounted on the mounting board, a gap is different between the die pad and the mounting board and between the signal connection lead and the mounting board. The tension of the solder to be used is different and the alignment is improved. Therefore, the time required for self-alignment can be shortened and the positional accuracy can be improved.

Since the groove is formed in at least a part of the signal connecting lead, even if the lower surface of the signal connecting lead is exposed from the sealing resin, the sealing resin is retained on the signal connecting lead. Power improves.

The lower surface of the exposed portion of the die pad is preferably located below the lower surface of the exposed portion of the signal connecting lead.

The difference in height between the lower surface of the exposed portion of the die pad and the lower surface of the exposed portion of the signal connecting lead is preferably 10 to 150 μm.

According to the method of manufacturing a resin-sealed semiconductor device of the present invention, an outer frame surrounding an area for mounting a semiconductor chip, a die pad for supporting the semiconductor chip, and the die pad connected to the outer frame. A first step of preparing a lead frame having a suspension lead and a signal connection lead connected to the outer frame, and the die pad being located below the signal connection lead; A second step of mounting a semiconductor chip having an electrode pad on the die pad, and a third step of electrically connecting the electrode pad of the semiconductor chip and the signal connecting lead through a thin metal wire, The sealing tape is attached to the sealing mold while the sealing tape is adhered to at least a part of the lower surface of the die pad of the lead frame and at least a part of the lower surface of the signal connecting lead. And a fifth step of sealing the die pad, the semiconductor chip, the signal connection lead and the thin metal wire with a sealing resin, and a sixth step of removing the sealing tape. At least a part of the lower surface of the die pad and at least a part of the lower surface of the signal connecting lead are exposed from the back surface of the sealing resin, and the lower surface of the exposed portion of the die pad is the signal connecting lead. Is a method for obtaining a resin sealing body located below the lower surface of the exposed portion of the.

According to this method, when the resin-sealed semiconductor device is mounted on the mounting substrate, a large tension of solder or the like below the die pad controls the position and time of self-alignment of the resin-sealed semiconductor device. Therefore, it is possible to reduce the mounting time, improve the accuracy of the mounting position, and improve the mountability.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The resin-encapsulated semiconductor device of the present invention has a common structure in which the lower surface of the die pad is exposed from the rear surface of the encapsulating resin, and various embodiments will be described below. explain.

(First Embodiment) FIG. 1 is a sectional view of a resin-sealed semiconductor device according to the first embodiment. However, in FIG. 1, the sealing resin 17 is treated as a transparent body,
Illustration of the suspension leads is omitted.

As shown in FIG. 1, the resin-encapsulated semiconductor device of this embodiment has a signal connecting lead 12, a die pad 13 for supporting a semiconductor chip, and a suspension lead for supporting the die pad 13. It is equipped with a lead frame. The semiconductor chip 15 is bonded onto the die pad 13 with an adhesive, and the electrode pad (not shown) of the semiconductor chip 15 and the signal connection lead 1 are connected.
2 are electrically connected to each other by a thin metal wire 16. Then, the signal connecting lead 12 and the die pad 1
3, suspension lead, semiconductor chip 15 and thin metal wire 16
Are sealed in the sealing resin 17.

Here, the feature of this embodiment is that the back surface side of the die pad 13 has a convex portion 13 at the central portion by half etching or the like.
It is a stepped shape so that it becomes a and there is a flange portion 13b around it, and only the lower part of this convex portion 13a protrudes from the back surface of the sealing resin. Therefore, in the state of being sealed by the sealing resin 17, the sealing resin 17 is thinly present below the flange portion 13b around the convex portion 13a of the die pad 13.

Further, the sealing resin 17 does not exist on the lower surface side of the signal connecting lead 12, the lower surface of the signal connecting lead 12 is exposed, and the lower surface of the signal connecting lead 12 serves as a mounting substrate. It becomes the connection surface. That is, the lower portion of the signal connection lead 12 is the external electrode 18.

The exposed convex portion 13a of the die pad 13 and the external electrode 18 originally do not have a resin burr which is a protruding portion of the resin in the resin sealing step,
In addition, the convex portion 13a of the die pad 13 and the external electrode 18 slightly project below the back surface of the sealing resin 17. Such a structure of the convex portion 13a of the die pad 13 and the external electrode 18 which does not have a resin burr and protrudes downward can be easily realized by a manufacturing method described later.

According to the resin-encapsulated semiconductor device of this embodiment, the back surface side of the die pad 13 has a stepped shape with the convex portion 13a at the central portion, and only the lower portion of the convex portion 13a is exposed from the sealing resin. Therefore, the sealing resin 17 is thinly present below the flange portion 13b of the die pad 13. Therefore, the sealing resin 17 for the die pad 13
Is increased, and the reliability of the resin-sealed semiconductor device is improved.

Further, since the holding force is increased, the adhesion between the sealing resin 17 and the die pad 13 is improved, so that it is possible to prevent the intrusion of moisture and humidity from the boundary between the two and to improve the moisture resistance. . Therefore, the reliability of the resin-sealed semiconductor device is further improved.

Moreover, since there is no resin burr on the exposed lower surface of the convex portion 13a of the die pad 13, the reliability of the joint between the convex portion 13a and the mounting substrate and the heat dissipation characteristic are improved.

In this embodiment, there is no outer lead serving as an external electrode terminal on the side of the signal connecting lead 12, and the signal connecting lead 1 corresponding to the inner lead is provided.
Since the lower portion of 2 serves as the external electrode 18, the semiconductor device can be downsized. Moreover, since the resin burr does not exist on the lower surface of the signal connection lead 12, that is, the lower surface of the external electrode 18, the reliability of the bonding with the electrode of the mounting substrate is improved. Further, since the external electrode 18 is formed so as to project from the surface of the sealing resin 17, the external electrode 18 is bonded to the electrode of the mounting substrate when mounting the resin-sealed semiconductor device on the mounting substrate. This means that the standoff height of is secured in advance. Therefore, the external electrode 1
8 can be used as an external terminal as it is, and it is not necessary to attach a solder ball to the external electrode 18 for mounting on the mounting board, which is advantageous in terms of manufacturing steps and manufacturing cost.

Next, a method of manufacturing the resin-sealed semiconductor device of this embodiment will be described with reference to the drawings. 2 to 6 are cross-sectional views showing the manufacturing process of the resin-encapsulated semiconductor device of this embodiment.

First, in the step shown in FIG. 2, the signal connecting leads 12 and the die pad 1 for supporting the semiconductor chip are formed.
A lead frame 20 provided with 3 and 3 is prepared.
In the figure, the die pad 13 is supported by suspension leads, but the suspension leads are not shown because they do not appear in this section. The outer side of the signal connecting lead 12 is connected to the outer frame of the lead frame 20, but since the outer frame is continuous with the signal connecting lead, no boundary appears on this step surface. Here, the back surface side of the die pad 13 is formed in a stepped shape in which the central portion becomes the convex portion 13a and the flange portion 13b exists around the convex portion 13a by half etching with the central portion masked. Further, the lead frame 20 to be prepared is a lead frame that is not provided with a tie bar that stops the outflow of the sealing resin during resin sealing.

In addition, the lead frame 20 in the present embodiment has a nickel (Ni) layer as a base plating, a palladium (Pd) layer thereon, and a thin film on the uppermost layer, as compared with a frame made of a copper (Cu) material. 3 is a metal-plated lead frame in which gold (Au) layers are plated. However, other than copper (Cu) material, 42 alloy material and the like can be used, and may be plated with a noble metal other than nickel (Ni), palladium (Pd), and gold (Au). It is not always necessary to use three-layer plating.

Next, in the step shown in FIG. 3, the semiconductor chip 15 is placed on the die pad of the prepared lead frame and the two are bonded to each other with an adhesive. This process is
This is a so-called die-bonding process. The member that supports the semiconductor chip is not limited to the lead frame, and a member that can support another semiconductor chip, such as a TAB tape or a substrate, may be used.

Then, in the process shown in FIG.
The semiconductor chip 15 and the signal connecting lead 1 bonded on
2 and 2 are electrically connected by a thin metal wire 16. This process is a so-called wire bond process. As the metal thin wire, an aluminum thin wire, a gold (Au) wire, or the like can be appropriately selected and used. In addition, the electrical connection between the semiconductor chip 15 and the signal connection lead 12 is made by the metal thin wire 16
It may be performed not through the bumps but through bumps or the like.

Next, in the step shown in FIG. 5, with the semiconductor chip 15 bonded to the die pad 13 of the lead frame, the sealing tape 21 is formed on the lower surface of the convex portion of the die pad 13 and the back surface of the signal connecting lead 12. Paste.

This sealing tape 21 is especially suitable for the die pad 1.
The sealing tape 21 serves to prevent the sealing resin from wrapping around the lower surface of the convex portion 13a of FIG. 3 and the rear surface of the signal connecting lead 12 during resin sealing. Of the die pad 13 due to the presence of
It is possible to prevent the resin burr from being formed on the lower surface of 3a or the back surface of the signal connecting lead 12. This sealing tape 21 is made of polyethylene terephthalate, polyimide,
It is a tape based on a resin containing polycarbonate as a main component as long as it can be easily peeled off after the resin is sealed and has resistance to a high temperature environment at the time of resin sealing. In this embodiment, a tape containing polyethylene terephthalate as a main component is used, and the thickness is 50 [μ
m].

Next, in the step shown in FIG. 6, the semiconductor chip 1
The lead frame to which 5 is bonded and the sealing tape 21 is attached is housed in a mold, and the sealing resin 17 is poured into the mold to perform resin sealing. Alternatively, the sealing tape 21 can be attached in the mold. At this time, the lower surface side of the convex portion 13a of the die pad 13 and the signal connecting lead 1
The tip end side (outer frame) of the signal connection lead 12 of the lead frame is pressed downward by a mold so that the sealing resin 17 does not wrap around on the back surface side of 2.

Finally, the sealing tape 21 attached to the lower surface of the convex portion 13a of the die pad 13 and the back surface of the signal connecting lead 12 is removed by peeling off. As a result, on the back surface side of the die pad 13, a structure in which only the lower portion of the convex portion 13a projects below the back surface of the sealing resin is obtained, and the external electrode 18 projecting from the back surface of the sealing resin 17 is formed. Then, the tip end side of the signal connecting lead 12 is cut off so that the tip end surface of the signal connecting lead 12 and the side surface of the sealing resin 17 are substantially flush with each other, so that the resin sealing type as shown in FIG. The semiconductor device is completed.

According to the manufacturing method of this embodiment, only a part of the protrusion 13a of the die pad 13 projects from the back surface of the sealing resin 17, and the flange 13b around the protrusion 13a.
It is possible to easily manufacture a resin-sealed semiconductor device in which the sealing resin 17 is present below.

Moreover, according to the manufacturing method of the present embodiment,
Before the resin encapsulation step, the encapsulating tape 21 is previously formed on the lower surface of the convex portion 13a of the die pad 13 and the rear surface of the signal connecting lead 12.
Since the sealing resin 17 does not wrap around, resin burrs do not occur on the convex portion 13a of the die pad 13 and the back surface of the signal connection lead 12 that serves as an external electrode.
Therefore, the resin burrs formed on the lower surface of the convex portion 13a of the die pad 13 and the external electrode 18 are removed by a water jet or the like as in the conventional method of manufacturing a resin-sealed semiconductor device in which the lower surface of the signal connection lead is exposed. do not have to. That is, by omitting the troublesome process for removing the resin burr, it is possible to simplify the process in the mass production process of the resin-encapsulated semiconductor device. Further, it is possible to eliminate the peeling of the metal plating layer of nickel (Ni), palladium (Pd), gold (Au) or the like of the lead frame and the adhesion of impurities, which may occur in the resin burr removal process by a water jet or the like. Therefore, it is possible to pre-plat each metal layer before the resin sealing step.

Although the resin burr removing step by the water jet can be omitted, a step of attaching the sealing tape is newly required, but the step of attaching the sealing tape 21 is more preferable than the water jet step. Since the cost is low and the process control is easy, the process can be surely simplified. Above all, in the conventionally required water jet process, the metal plating of the lead frame is peeled off, and quality problems such as the adhesion of impurities occur, but in the method of the present embodiment, by applying the sealing tape, The fact that the water jet is unnecessary and the plating can be removed is a great process advantage. In addition, even if resin burrs may occur due to the sealing tape attachment state, etc., since it is an extremely thin resin burr, it is possible to remove the resin burrs by water jet processing with low water pressure and prevent plating peeling. A layer pre-plating process is possible.

As shown in FIG. 6, in the resin sealing step, the sealing tape 21 is softened and thermally contracted by the heat of the sealing die, so that the convex portion 1 of the die pad 13 is formed.
3a and the lead 12 for signal connection largely dig into the sealing tape 21, and the convex portion 13a of the die pad 13 and the sealing resin 1
7, a step is formed between the back surface of the signal connecting lead 12 and the back surface of the sealing resin 17.
Therefore, the convex portion 13a of the die pad 13 and the signal connecting lead 12 have a structure protruding from the back surface of the sealing resin 17, and the standoff height of the convex portion 13a of the die pad 13 and the external electrode which is the lower portion of the signal connecting lead 12 are formed. A protrusion amount of 18 (standoff height) can be secured. For example, in this embodiment, since the thickness of the sealing tape 21 is 50 μm, the protrusion amount can be about 20 μm, for example. In this way, by adjusting the thickness of the sealing tape 21, the amount of protrusion of the external electrode 18 from the sealing resin can be maintained at an appropriate amount. This means that the standoff height of the external electrode 18 can be controlled only by setting the thickness of the sealing tape 21, and it is not necessary to separately provide a means or process for controlling the standoff height amount. This is an extremely advantageous point in the cost of process control in the mass production process. The thickness of the sealing tape 21 is preferably about 10 to 150 μm.

Regarding the sealing tape 21 used,
A material having a predetermined hardness, thickness, and heat-softening property can be selected according to a desired protrusion amount.

However, in the first embodiment, the standoff height of the protrusion of the die pad 13 or the external electrode 18 may be adjusted by adjusting the pressure applied to the sealing tape 21, for example, the standoff height. It is also possible to set the height to almost “0”. In that case, since the sealing resin 17 exists thickly below the flange portion 13b around the convex portion 13a on the back surface side of the die pad 13, there is an advantage that the holding force of the sealing resin 17 with respect to the die pad 13 is further improved.

(Second Embodiment) Next, a second embodiment will be described. The basic structure of the resin-encapsulated semiconductor device in this embodiment is the same as the structure shown in FIG. 1 in the first embodiment, but only the shape of the die pad is different. Therefore, in the present embodiment, only the shape of the die pad will be described, and description of other parts will be omitted.

-First Specific Example- FIG. 7A is a plan view of a die pad 13 according to a first specific example of the present embodiment, and FIG. 7B is a VIIb- shown in FIG. 7A.
FIG. 7 is a sectional view taken along line VIIb. As shown in FIGS. 7A and 7B, the die pad 13 according to this specific example has small circular through holes 30a formed at four corners. However, the through hole 30a is formed in the semiconductor chip 1
5 is formed outside the mounting area. Further, although the convex portion is not formed on the back surface side of the die pad 13, the convex portion may be formed.

According to the resin-encapsulated semiconductor device of the first specific example of this embodiment, the through hole 30a is formed in the die pad 13.
Since the sealing resin is formed in the through hole 30a, the sealing resin 1 for the die pad 13 is formed.
The holding power of 7 is greatly improved. Further, as a result, the adhesiveness between the die pad 13 and the sealing resin 17 is increased, so that it is possible to prevent the ingress of water, moisture and the like from the boundary portion between the two and to improve the moisture resistance. .

Here, in the manufacturing process of the resin-encapsulated semiconductor device, the resin is sealed from the through-hole by sealing the resin by adhering the sealing tape to the lower surface of the die pad 13 as in the first embodiment. It never leaks. That is, in the conventional resin sealing method, when a through hole is provided in the die pad exposed from the sealing resin, the sealing resin leaks from the through hole to the back surface side of the die pad. Moreover, since the pressing force of the sealing die is not applied to the die pad, the sealing resin leaks more than the back surface side of the signal connecting lead, which may reduce the product value. Therefore, in the resin-sealed semiconductor device of the type in which the back surface of the die pad is exposed from the encapsulation resin regardless of the case where the die pad is embedded in the encapsulation resin, the structure in which the through hole is provided in the die pad is difficult to adopt. It was On the other hand, in the present embodiment, a method of sealing the resin by adhering the sealing tape to the back surface of the die pad is adopted, so that the through hole 30a is provided in the die pad 13 without causing a problem, and the sealing resin The holding power can be increased.

As shown in the modified example of FIG. 8, the through hole 30b may be provided in the shape of an elongated hole instead of the shape of a small circle. In this case, since the cross-sectional area of the through hole 30b becomes larger, the holding force of the sealing resin 17 with respect to the die pad 13 is further improved.

The semiconductor chip 15 is the die pad 1
It may have a size large enough to protrude from 3.

Even if a blind hole that is not a through hole is formed, the effect of increasing the holding force of the sealing resin 17 can be obtained.

-Second Specific Example- FIG. 9A is a plan view of a die pad 13 according to a second specific example of the present embodiment, and FIG. 9B is IXb-IX shown in FIG. 9A.
It is sectional drawing in line b. As shown in FIGS. 9A and 9B, in the die pad 13 according to the present specific example, stepped through holes 30c each having a wide lower side are formed at four corners. The through hole 30c is formed in the semiconductor chip 1
5 is formed outside the mounting area. Further, the point that a convex portion is formed on the back surface side of the die pad 13 by half etching or the like is the same as the structure of the die pad 13 in the first embodiment, but the through hole 30c is provided in the convex portion. There is.

According to the resin-sealed semiconductor device of the second specific example of the present embodiment, since the die pad 13 has the stepped through hole 30c having a wide lower side, the sealing resin 17 for the die pad 13 is formed. The holding power is greatly improved.

As shown in the modification of FIG. 10, the through hole 30d may be provided in the shape of an elongated hole instead of the small circle. In this case, since the cross-sectional area of the through hole 30d becomes larger, the holding force of the sealing resin 17 with respect to the die pad 13 is further improved. In particular, in the case of the through hole 30d in the shape of an elongated hole, by making the shape long and thin, the area of the die pad 13 inside the through hole 30d can be secured to be large, so that the restriction on the size of the semiconductor chip to be mounted is relaxed. You can In other words, it is possible to reduce the size of the resin-sealed semiconductor device with respect to semiconductor chips of the same size.

The through hole 30c or 30d does not necessarily have to be provided outside the mounting area of the semiconductor chip 15, but in that case, the sealing resin 17 can flow from the back side of the die pad 13. It is preferable to provide the through hole 30c or 30d in a portion, that is, in the peripheral region of the convex portion.

In the case where the semiconductor chip is flip-chip connected to the die pad via the bump, a gap is formed between the semiconductor chip and the die pad to ensure that the through hole is located at any position. The sealing resin wraps around. Therefore, the position of the through hole is not limited in principle.

Further, the semiconductor chip 1 shown in FIGS.
5 may have a size protruding outside the through holes 30c and 30d.

(Third Embodiment) FIG. 11A shows a third embodiment.
11B is a plan view of the resin-encapsulated semiconductor device according to the embodiment of FIG. 11, and FIG. 11B is a sectional view taken along line XIb-XIb shown in FIG. 11A. However, in FIG. 11A, the sealing resin 17 is treated as a transparent body, and the semiconductor chip 15 has a contour indicated by a broken line.
Are not shown.

As shown in FIGS. 11A and 11B, the resin-sealed semiconductor device of this embodiment has a signal connecting lead 12 and a die pad 13 for supporting a semiconductor chip.
And a suspension lead 1 for supporting the die pad 13
4 is provided with a lead frame. Then, the semiconductor chip 15 is bonded onto the die pad 13 with an adhesive, and the electrode pads (not shown) of the semiconductor chip 15 and the signal connecting leads 12 are electrically connected to each other by the thin metal wires 16. . The signal connecting leads 12, the die pad 13, the suspension leads 14, the semiconductor chip 15 and the thin metal wires 16 are sealed in a sealing resin 17. The inner region on the back surface side of the signal connecting lead 12 is half-etched. Conversely speaking,
An area of the signal connecting lead 12 which is not half-etched is a convex portion.

Here, the characteristic portion of the resin-sealed semiconductor device according to this embodiment will be described. Die pad 13
Are down set by the depressing portion 19 of the suspension lead 14 so as to be located below the signal connecting lead 12. Further, the sealing resin 17 does not exist on the rear surface side of the die pad 13 and the lower surface side of the convex portion of the signal connecting lead 12. That is, the back surface of the die pad 13 is exposed to serve as a heat dissipation surface, the lower surface of the convex portion of the signal connecting lead 12 is exposed, and the lower portion including the lower surface of the convex portion of the signal connecting lead 12 becomes the external electrode 18. There is. As described in the first embodiment, this structure can be easily realized by bringing a sealing tape into close contact with the lower surfaces of the die pad 13 and the signal connecting lead 12 to perform resin sealing. Then, the back surface of the die pad 13 and the external electrode 1
8 does not originally have a resin burr which is a protruding portion of the resin in the resin sealing step, and the die pad 13 and the external electrode 18 slightly project below the back surface of the sealing resin 17. The structure of the die pad 13 and the external electrode 18 which do not have such resin burrs and protrude downward is as follows.
As described in the first embodiment, the die pad 13
Also, it can be easily realized by bringing a sealing tape into close contact with the lower surface of the signal connecting lead 12 to perform resin sealing.

According to the resin-sealed semiconductor device of the present embodiment, the die pad 13 is downset so as to be located below the signal connection lead 12 (external electrode 18), and therefore the following effects are obtained. Can be demonstrated.

FIG. 12 is a sectional view showing a state in which the resin-sealed semiconductor device according to this embodiment is mounted on the mounting substrate 40. As shown in FIG.
1, the heat radiation pad 42, the external electrode 18 of the resin-sealed semiconductor device, and the die pad 13 are aligned and soldered. At that time, the external electrode 18-the electrode 41
Since the thickness of the solder 43a interposed between the solder 43a and the solder 43b interposed between the die pad 13 and the heat dissipation pad 42 is different, the tension acting between the external electrode 18 and the electrode 41,
The tension applied between the die pad 13 and the heat radiation pad 42 is different from each other. As described above, as a result of the difference in the solder tension between the central portion and the peripheral portion of the resin-encapsulated semiconductor device, the self-alignment property of the resin-encapsulated semiconductor device with respect to the mounting substrate 40 is improved, and the position is swift and accurate. The resin-encapsulated semiconductor device can be mounted on.

Further, in the central portion of the resin-sealed semiconductor device, the die pad 13 having a large area is strongly bonded onto the heat dissipation pad 42 of the mounting substrate 40, so that the external electrode 18 and the electrode 41 are connected after the connection. Various stresses act. Therefore, it is possible to stabilize the connection of the signal connection lead 12 that is easily removed by exposing the lower surface, and the reliability is improved as a whole.

Although the lower surface of the die pad 13 is lower than the lower surface of the external electrode 18 in this embodiment, the self-alignment property can be improved even if the height relationship is reversed. However, when the lower surface of the die pad 13 is lower, the gap between the die pad 13 and the heat radiation pad 42 becomes smaller, so that the tension of this wide portion becomes large, and as a result, the above-mentioned effect is more remarkably obtained.

(Fourth Embodiment) Next, a fourth embodiment will be described. In the present embodiment, as in the first embodiment, a specific example for suppressing deformation of the die pad 13 when a sealing tape is laid below the lead frame to perform resin sealing will be described.

-First Specific Example- FIG. 13A is a plan view of a lead frame according to a first specific example of the present embodiment, and FIG. 13B is FIG. 13A.
FIG. 13 is a cross-sectional view of the lead frame taken along the line XIIIb-XIIIb shown in FIG. As shown in FIGS. 13 (a) and 13 (b), suspension leads 14 extending from the four corners of the die pad 13 and connected to the outer frame 46 are provided, and the suspension leads 14 function as springs. A bent portion 45 having a character shape is provided. Further, the lower surface of the die pad 13 is lower than the lower surface of the outer frame 46, and there is a predetermined height difference between them.

By thus setting the lower surface position of the die pad 13 lower than the lower surface position of the outer frame 46, when the sealing tape is brought into close contact with the lower surface of the lead frame in the resin sealing step, sealing is performed. A pressing force can also be applied to the tape from the die pad 13. That is, since the die cavity is located above the die pad 13, the die clamping force applied between the upper die and the lower die of the sealing die does not act on the die pad 13 as it is. Therefore, the action described in the first embodiment in which the die pad 13 bites into the sealing tape and the lower portion of the die pad 13 projects from the back surface of the sealing tape may be reduced. On the other hand, in the case of this example, the outer frame 46
Since the lower surface of the die pad 13 is lower than the lower surface of the die pad, when the mold clamping force of the sealing die is applied to the outer frame 46, a pressing force is applied to the die pad 13 via the suspension leads 14 and the die pad 13 is sealed. By digging into the tape, a large amount of protrusion of the die pad 13 from the sealing resin 17 can be secured. And the suspension lead 14 of the lead frame
By providing the bent portion 45 on the suspension lead 14
The deformation of the die pad 13 is absorbed in the bent portion 45, so that the deformation of the die pad 13 can be suppressed.

In the shape shown in FIG. 13B, the die pad 13 has a U-shaped bent portion 4 due to the entire inclination.
Although it is lower than 5, it is possible to lower the die pad 13 by providing steps on both sides of the U-shaped bent portion 45.

-Second Specific Example- FIG. 14A is a plan view of a lead frame according to a second specific example of the present embodiment, and FIG. 14B is FIG. 14A.
FIG. 9 is a cross-sectional view taken along line XIVb-XIVb in FIG.

As shown in FIGS. 14A and 14B, in the lead frame of this specific example, the suspension lead 47 is interposed between the signal connection lead 12 connected to the outer frame 46 and the die pad 13. ing. That is, the suspension lead 47
The die pad 13 is supported by the outer frame 46 via the signal connection leads 12. The suspension lead 47 is provided with a U-shaped bent portion 48 for giving a spring effect. However, in the present embodiment, a part of the back surface of the signal connection lead 12 is half-etched, and the non-half-etched part is a convex portion. Further, two grooves that are orthogonal to the direction in which the signal connecting leads 12 extend are formed on the front side of the signal connecting leads 12.

FIGS. 15A and 15B are sectional views showing a part of the manufacturing process of a resin-sealed semiconductor device using this lead frame.

First, as shown in FIG. 15A, the semiconductor chip 15 is mounted on the die pad 13, and the electrode pad of the semiconductor chip 15 and the region sandwiched between the two grooves of the signal connecting lead 12 are made of metal. Connected by a thin wire 16. Then, the sealing tape 21 is attached to the die pad 13 of the lead frame.
To adhere.

Next, as shown in FIG. 15B, the lead frame and the semiconductor chip 15 are placed between the upper die 50a and the lower die 50b of the sealing die 50, and the upper die 50a. −
The mold clamping force between the lower molds 50b is the outer frame 46 of the lead frame.
Join in. When the outer frame 46 is pressed by this mold clamping force, the signal connection lead 12 and the suspension lead 48 are attached to the die pad 13 located below the outer frame 46.
The pressing force is transmitted via. Therefore, the die pad 1
3 bites into the sealing tape 21, and the convex portion of the signal connecting lead 12 and the outer frame 46 also bit into the sealing tape 21. In this state, the sealing resin 17 is poured into the die cavity of the sealing mold 50 to embed the die pad 13, the signal connecting leads 12 and the like in the sealing resin 17.

In this specific example, also in the sealing die, the portion corresponding to the die pad 13 is provided slightly lower than the portion corresponding to the outer frame 46 (and the signal connecting leads 12). Therefore, after the resin sealing, although the height difference between the die pad 13 and the outer frame 46 (leads 12 for signal connection) is considerably reduced, the lower surface of the die pad 13 is located below.

After the resin sealing step is completed, the sealing tape 21 is peeled off from the resin sealing body, and the outer frame 46 is removed by cutting the connecting portion between the outer frame 46 and the signal connecting lead 12. Then, a resin-sealed semiconductor device is obtained in which the die pad 13 and the protrusions (external electrodes) of the signal connection leads 12 are exposed from the sealing resin.

According to this example, since the suspension lead 47 is provided between the signal connecting lead 12 and the side portion of the die pad 13, the mold clamping force applied to the outer frame 46 is increased as compared with the first example. The structure can be more effectively transmitted to the die pad 13, and thus the structure in which the lower surface of the die pad 13 is exposed from the sealing resin can be realized more reliably.

In the formed resin-encapsulated semiconductor device, the lower surface of the die pad 13 is provided with the signal connecting lead 12.
Since it is located below the lower surface of the, the above-described effect of improving the self-alignment property can be obtained.

-Third Specific Example- When the suspension leads 47 are provided between the signal connecting leads 12 and the sides of the die pad 13 as in the second specific example, the suspension leads 47 are mounted in the semiconductor chip 15. Depending on the type of element (for example, a bipolar transistor) used, a problem may occur when the signal connection lead 12 connected to the suspension lead 47 is used for signal transmission. Therefore,
In this embodiment, a device for avoiding such a problem will be described.

FIG. 16 is a view showing a part of the lead frame in the resin sealing process of the resin sealing type semiconductor device in this example. In this specific example, a part of the suspension lead 47 is exposed from the sealing resin. That is, the lead frame is formed in a shape such that the rising portion 49 of the bent portion 48 of the suspension lead 47 bites into the sealing tape 21 in the sealing die. Then, after the resin sealing step is completed, this rising portion 49 is cut by a laser or the like as shown by the dotted line in FIG. By cutting a part of the suspension lead 47 in this manner, the signal connection lead 12 connected to the suspension lead 47 and the die pad 13 are brought into an electrically non-conductive state. Even if 12 is used for signal transmission, no trouble occurs. On the other hand, since it is after being sealed with the sealing resin, the function of the suspension lead 47 has already been fulfilled, and even if it is cut in this way, no problem occurs. In addition, the suspension lead 4 is used even after the resin sealing step.
If the spring function of 7 is left as it is, the residual stress exists in the sealing resin, which may reduce the reliability, but such a problem can be reliably avoided.

After the resin sealing step, the rising portion 49 of the suspension lead 47 may be cut from above the sealing tape 21 with the sealing tape 21 still attached. In this case, since the periphery of the cut portion is covered with the sealing tape 21, even if the melted material due to the laser scatters around, the scattered material can be easily removed from the resin-sealed semiconductor device by peeling off the sealing tape 21. There is an advantage that it can be removed.

-Fourth Specific Example- When cutting a part of the suspension lead 47 as in the third specific example, it may be time-consuming to cut. Therefore,
In this specific example, a device for facilitating the cutting of the suspension lead will be described.

FIG. 17 is a sectional view showing a part of the lead frame according to the fourth example. As shown in the figure, a cutout is provided on the front side at the rising portion 49 of the bent portion 48 of the suspension lead 47 in this example.

In this example, since the notch is provided in the rising portion 49 of the suspension lead 47, the work of cutting the rising portion 49 with a laser or the like can be easily and quickly performed after the resin sealing step is completed. it can.

As described in the above specific examples, the resin-sealed semiconductor device obtained by the manufacturing process of each specific example in the present embodiment has the same die pad as the resin-sealed semiconductor device shown in FIG. 13 and the signal connection lead 12 are partially exposed from the sealing resin. In particular, in each specific example of the present embodiment, since the height difference is provided between the outer frame and the die pad, the mold clamping force applied to the outer frame is reliably transmitted to the die pad through the suspension lead, and the sealing tape The die pad can be bitten into, and the structure in which the lower portion of the die pad is exposed from the sealing resin can be reliably obtained.

Further, as shown in the drawings relating to each concrete example of the present embodiment, when it is desired to position the lower surface of the die pad below the lower surface of the signal connecting lead as in the third embodiment, Adopting the structure of the suspension lead of the embodiment can exert a remarkable effect.

Also in this embodiment, it is possible to adopt a structure in which the die pad 13 is provided with a convex portion as shown in FIG. 1 and only the convex portion is exposed from the sealing resin.
This is more preferable because the holding force of the sealing resin 17 with respect to the die pad 13 can be increased.

(Fifth Embodiment) In this embodiment, a resin sealing method for adjusting the amount of protrusion of the die pad from the sealing resin will be described.

FIG. 18 is a sectional view showing a resin encapsulation process in the process of manufacturing the resin-encapsulated semiconductor device according to this embodiment. As shown in the figure, the upper die 50a and the lower die 50
The semiconductor die 15 is mounted on the die pad 13 by using a sealing die composed of b, and the electrode pad of the semiconductor chip and the signal connecting lead 12 are connected by the fine metal wire 16 is a lower die of the sealing die. It is mounted on the mold 50b, and resin sealing is performed with the sealing tape 21 in close contact with the lower surface of the lead frame.

Here, the feature of the manufacturing method of the present embodiment is that
In the lower die 50b, a concave first relief portion 52 is provided in a region of the lead frame facing the signal connection lead 12 (and the outer frame 46), and a concave second relief portion 52 is provided in a region facing the die pad 13. The point is that each part 53 is provided.

By providing the relief parts 52, 53 in the sealing die in this way, the relief tape 52,
By escaping to the direction 53, the amount of the signal connecting lead 12 and the die pad 13 biting into the sealing tape 21 is reduced. As a result, not only the mold clamping force of the sealing mold but also the escape portion 5
Depending on the depth of 2, 53, the amount of protrusion of the portion to be protruded can be adjusted to a desired value, and the amount of resin burr generated can also be minimized.

(Sixth Embodiment) In this embodiment, a resin sealing method for ensuring a large amount of protrusion of the die pad from the sealing resin will be described.

FIG. 19 is a sectional view showing a resin encapsulation process in the manufacturing process of the resin-encapsulated semiconductor device according to this embodiment. As shown in the figure, the upper die 50a and the lower die 50
The semiconductor die 15 is mounted on the die pad 13 by using a sealing die composed of b, and the electrode pad of the semiconductor chip and the signal connecting lead 12 are connected by the fine metal wire 16 is a lower die of the sealing die. It is mounted on the mold 50b, and resin sealing is performed with the sealing tape 21 in close contact with the lower surface of the lead frame.

Here, the feature of the manufacturing method of the present embodiment is that
A through hole 25 is formed in a portion of the sealing tape 21 located below the die pad 13, and a suction hole 54 is provided in a region of the lower die 50b facing the die pad 13. Through hole 2 of this sealing tape 21
5 is larger than the suction hole 54 of the lower mold 50b,
It is easy to control so that 4 is surely located at the position of the through hole 25. The suction hole 54 is communicated with the vacuuming device, and the suction action of the vacuuming device biases the die pad 13 toward the suction hole 54 to increase the amount of bite into the sealing tape 21. Has been done.

According to the method of manufacturing the resin-encapsulated semiconductor device of this embodiment, the die pad 13 is sealed by providing the sealing tape 21 with the through hole 25 and the sealing die with the suction hole 54. The amount of bite into the tape 21 increases. As a result, the die pad 13 having a large area and in which the mold clamping force of the sealing mold is hard to be transmitted can be largely projected from the sealing resin.

However, the method of the present embodiment can be applied not only to the die pad but also to a component that is to be surely projected from the sealing resin.

(Other Embodiments) In each of the above-mentioned embodiments, the electrode pads of the semiconductor chip and the signal connecting leads are connected by the metal thin wires, but the connecting member of the present invention is limited to the metal thin wires. Not a thing. That is, depending on the embodiment, a resin-encapsulated semiconductor device in which a semiconductor chip formed by flip-chip mounting on a substrate via bumps is encapsulated in an encapsulating resin may be used.

A hole for vacuuming is provided in the mold, and resin sealing is performed while vacuuming the sealing tape 21 to suppress the generation of wrinkles in the sealing tape, and to prevent the backside of the sealing resin. It can also be flattened.

[0100]

According to the resin-encapsulated semiconductor device and the method of manufacturing the same of the present invention, the time required for self-alignment at the time of mounting the semiconductor device on a mounting substrate can be shortened, the positional accuracy can be improved, and the mountability can be improved. Can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a resin encapsulation type semiconductor device according to a first embodiment of the present invention through a sealing resin.

FIG. 2 is a cross-sectional view showing a step of preparing a lead frame in the manufacturing process of the resin-encapsulated semiconductor device of the first embodiment.

FIG. 3 is a cross-sectional view showing a step of joining a semiconductor chip onto a die pad in the manufacturing process of the resin-encapsulated semiconductor device of the first embodiment.

FIG. 4 is a cross-sectional view showing a step of forming thin metal wires in the manufacturing process of the resin-encapsulated semiconductor device of the first embodiment.

FIG. 5 is a cross-sectional view showing a step of laying a sealing tape under a lead frame in the manufacturing process of the resin-sealed semiconductor device of the first embodiment.

FIG. 6 is a cross-sectional view showing a resin encapsulation process in the process of manufacturing the resin-encapsulated semiconductor device of the first embodiment.

FIG. 7 is a plan view and a sectional view of a lead frame according to a first example of the second embodiment of the present invention.

FIG. 8 is a plan view of a lead frame according to a modification of the first example of the second embodiment of the present invention.

FIG. 9 is a plan view and a cross-sectional view of a lead frame according to a second example of the second embodiment of the present invention.

FIG. 10 is a plan view of a lead frame according to a modification of the second specific example of the second embodiment of the present invention.

FIG. 11 is a plan view and a cross-sectional view of a resin-sealed semiconductor device according to a third embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a state in which the resin-sealed semiconductor device according to the third embodiment is mounted on a mounting board.

FIG. 13 is a plan view and a cross-sectional view of a lead frame according to a first example of the fourth embodiment of the present invention.

FIG. 14 is a plan view and a sectional view of a lead frame according to a second example of the fourth embodiment of the present invention.

FIG. 15 is a cross-sectional view showing a part of a manufacturing process of a resin-sealed semiconductor device using a lead frame according to a second example of the fourth embodiment of the present invention.

FIG. 16 is a diagram showing a part of a lead frame in a resin-sealing process of a resin-sealed semiconductor device according to a third example of the fourth embodiment of the present invention.

FIG. 17 is a diagram showing a part of a lead frame in a resin-sealing process of a resin-sealed semiconductor device in a fourth specific example of the fourth embodiment of the present invention.

FIG. 18 is a cross-sectional view showing a resin-sealing step in the manufacturing process of the resin-sealed semiconductor device according to the fifth embodiment of the present invention.

FIG. 19 is a cross-sectional view showing a resin-sealing step in the manufacturing process of the resin-sealed semiconductor device according to the sixth embodiment of the present invention.

FIG. 20 is a cross-sectional view of a conventional resin-sealed semiconductor device of a type having an external electrode on the back surface side.

[Explanation of symbols]

12 signal connection leads 13 die pad 14 Hanging lead 15 semiconductor chips 16 thin metal wires 17 Sealing resin 18 External electrode 21 sealing tape 25 through holes 30 through holes 40 mounting board 41 electrodes 42 Heat dissipation pad 43 Solder 45 Bend 46 Outer frame 47 hanging lead 48 Bend 49 Rise 50a Upper mold 50b Lower mold 52 First relief part 53 Second relief part 54 Suction hole

Claims (5)

(57) [Claims] 1. A semiconductor chip having an electrode pad, a die pad supporting the semiconductor chip, a signal connecting lead, a connecting member electrically connecting the electrode pad of the semiconductor chip and the lead, and the die pad. A semiconductor chip, a signal connecting lead and a sealing resin for sealing the connecting member, wherein at least a part of the lower portion of the die pad and at least a part of the lower portion of the signal connecting lead are made of the sealing resin. A resin-encapsulated semiconductor device, wherein the height of the exposed lower surface of the die pad is different from that of the exposed lower surface of the signal connecting lead. 2. The resin-sealed semiconductor device according to claim 1, wherein a groove is formed in at least a part of the signal connection lead. 3. The resin-sealed semiconductor device according to claim 1, wherein the lower surface of the exposed portion of the die pad is located lower than the lower surface of the exposed portion of the signal connecting lead. A resin-encapsulated semiconductor device characterized in that 4. The resin-sealed semiconductor device according to claim 1, wherein the lower surface of the exposed portion of the die pad and the exposed portion of the signal connection lead. The height difference with the lower surface of the resin-molded semiconductor device is 10 to 150 μm. 5. An outer frame surrounding an area for mounting a semiconductor chip, and a die pad for supporting the semiconductor chip,
A suspension lead for connecting the die pad to the outer frame, and a signal connection lead connected to the outer frame,
And a first step of preparing a lead frame in which the die pad is located below the signal connecting leads, a second step of mounting a semiconductor chip having an electrode pad on the die pad, A third step of electrically connecting the electrode pad of the semiconductor chip and the signal connecting lead through a thin metal wire, and at least a part of the lower surface of the die pad of the lead frame and at least one of the lower surface of the signal connecting lead. A fourth step of mounting the sealing tape on the sealing mold while closely contacting the sealing tape with the portion; and a step of sealing the die pad, the semiconductor chip, the signal connecting lead and the thin metal wire with a sealing resin. 5 and the sixth step of removing the sealing tape, and at least a part of the lower surface of the die pad and the lower surface of the signal connecting lead. And the lower surface of the exposed portion of the die pad is located below the lower surface of the exposed portion of the signal connection lead. A method for manufacturing a resin-encapsulated semiconductor device, which comprises obtaining a stopper.