JPH07249708A - Semiconductor device and its mounting structure - Google Patents

Abstract

(57) [Abstract] [Purpose] An object is to obtain a semiconductor device capable of improving electrical characteristics, mainly insulating characteristics, and significantly reducing the thickness, and a structure for mounting the semiconductor device on a substrate. [Structure] An opening 13 larger than the chip 12 is provided in a die pad 11 of a lead frame 10 for mounting the chip 12, and a heat resistant insulating film 14 is provided on the die pad 11.
And the chip 12 is mounted on the insulating film 14. There are a plurality of small holes 21 in the portion of the insulating film 14 that overlaps the die pad 11, and when the package is mounted on the substrate 23, the die pad 11 and the conductor portion on the substrate 23 are separated by the solder 22 through these small holes 21. To be joined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a structure for mounting it on a substrate, and more particularly to a resin mold-sealed thin surface mount package having excellent electrical characteristics and a method for manufacturing the same. 2. Description of the Related Art In recent years, semiconductor devices having excellent electrical characteristics have been demanded as the density and speed of electronic equipment systems have increased.

[0002]

2. Description of the Related Art Heretofore, a number of surface mount packages have been announced in which constituent parts including a semiconductor chip are hermetically sealed with a resin in order to improve electrical characteristics, particularly electrical insulation characteristics. There are problems such as an increase in the number of steps in manufacturing the lead frame for mounting.

[0003]

Therefore, in the present invention, the conventional lead frame manufacturing equipment is used as it is to solve various electrical problems, and until now, it has been used for power supply or grounding. It is an object of the present invention to provide a semiconductor device and a mounting structure thereof that can be integrated by allowing a large number of leads to escape from the package surface to the substrate and reduce the number of pins as a whole.

[0004]

According to a first aspect of the present invention, a die pad of a lead frame for mounting a semiconductor chip is provided with an opening larger than the semiconductor chip, and the heat resistant insulating film is formed so as to cover the opening. Is provided on the back surface of the die pad, and the semiconductor chip is mounted on the insulating film in the opening.

According to a second aspect of the present invention, the lead frame has a plurality of inner leads and outer leads connected to the respective inner leads, and the semiconductor chip and at least the inner leads are connected by wires, and the semiconductor chip 2. The semiconductor package is configured by integrally sealing a region including the inner lead and the wire with a resin mold, and the insulating film is exposed on a surface of the package. The semiconductor device is provided.

According to the third aspect, between the inner lead used for power supply or ground among the plurality of inner leads and the die pad, between the die pad and the power supply or ground pad of the semiconductor chip, and the signal. The semiconductor device according to claim 2, wherein the other inner lead used for the purpose and the signal pad of the semiconductor chip are electrically connected via wires, respectively.

According to a fourth aspect of the present invention, the die pad is divided into a plurality of pieces while being electrically insulated from each other, and one of the divided die pad portions is used as a power plane and the other die pad portion is used as a ground plane. The power plane is electrically connected to the power inner lead and the power pad of the semiconductor chip, and the ground plane is electrically connected to the ground inner lead and the ground pad of the semiconductor chip, respectively. A semiconductor device according to claim 2 is provided.

According to the present invention, the connection between the power supply or ground plane and the pad of the semiconductor chip is a wire, and the connection between the power supply or ground plane and the inner lead is a wire or an integral structure. The semiconductor device according to claim 4, wherein the semiconductor devices are connected by direct connection. According to claim 6, a plurality of small holes are provided in a portion of the insulating film overlapping with the die pad so that the die pad is exposed to the surface of the package through the small holes, and the package is mounted on a substrate. The mounting structure for a semiconductor device according to claim 2, wherein the die pad portion and the conductor portion on the substrate are joined by soldering through the small holes.

[0009]

According to the present invention, since the semiconductor chip is arranged on the insulating film in the opening, the thickness of the manufactured semiconductor device (package) can be thinned by the resin thickness under the die pad, Since it is a tape, it is insulated. According to the third aspect, since the die pad can be used as a plane for power supply or grounding, electrical wiring by wire bonding or the like can be easily performed.

According to the fourth aspect, the die pad is divided into a plurality of pieces, and one of the divided die pad portions is used as a power plane and the other die pad portion is used as a ground plane. Wiring can be further facilitated. In claim 5, if the plane for power supply or ground and the inner lead are integrally and directly connected, an electrical connection structure is formed when a lead frame is manufactured by press (stamping) processing or etching processing. In addition, since it is not necessary to make a connection between them by wire bonding or the like, it is possible to more easily carry out wiring and wiring work.

According to the sixth aspect, when the package is mounted on the board, solder paste or solder balls are formed in the small holes provided in the insulating film to form a solder joint with the conductor portion on the board. This can be done easily, and by combining such bonding between the die pad and the substrate and bonding between the usual outer leads and the substrate, the mounting of the package on the substrate can be made more reliable, and the package and the substrate can be It is possible to efficiently perform electrical connection between the and, to improve the electrical characteristics, and to increase the number of pins.

[0012]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1A to 1G show manufacturing steps for obtaining an ultrathin semiconductor device or semiconductor package of the present invention. First, in FIG. 1A, the lead frame is shown in a plan view. A semiconductor chip 12 to be mounted on the die pad portion 11 of the lead frame 10 (see FIG.
(D)) A larger rectangular opening 13 is provided. Such openings 13 can be formed at the same time when the lead frame 10 is formed by a press (stamping) process or an etching process. Next, FIG.
In (b) and (c), a heat resistant resin film 14 made of polyimide or the like having the same size and shape as the die pad portion 11 is attached to the back surface of the lead frame 10 so as to cover the opening 13. 1 (b) is a view of the lead frame as seen from the back side, the shaded portion is the resin film 14, FIG. 1 (c) is a sectional view showing the same state, and 16 is an inner lead. is there. Note that the die pad 11 portion is the offset portion 30 of the dam bar.
In FIGS. 1A and 1C, it is located below the surface of the lead frame 10.

Next, as shown in FIGS. 1D and 1E, the semiconductor chip 12 is adhered onto the resin film 14, and the semiconductor chip 1 is bonded by wire bonding (15).
2 and the inner lead 16 of the lead frame are connected. It is to be noted that FIG. 1D is a plan view of the lead frame as seen from above, and a hatched portion indicates the resin film 14. In addition, FIG. 1E shows the same state in a sectional view.
When the insulating film 14 has no adhesive force or when the adhesive force is not sufficient, another organic adhesive (not shown) is applied between the semiconductor chip 12 and the insulating film 14,
The semiconductor chip 12 is bonded onto the resin film 14 by contact.

Next, as shown in FIGS. 1F and 1G, the semiconductor chip 12 and the peripheral portion including the wire bonding portion, the inner leads 16 and the like are hermetically sealed with a molding resin 18 to complete a semiconductor device or package. To do. In this case, the resin film 14 is exposed on the surface of the semiconductor device. Note that FIG. 1F shows the completed semiconductor device, and the shaded portion shows the mold resin 18. Further, FIG. 1G shows the same state as seen from the back side, and the broken line portion shows the die pad portion 11.

The semiconductor device manufactured in this manner is
As shown in FIG. 1F, since the resin film 14 is completely exposed on the outer surface of the package, the thickness t of the device or the package is reduced (for example, t is 1 mm or less) to achieve a thin structure. be able to. Further, since the semiconductor chip 12 and the die pad 11 are completely insulated by the resin film 12, a semiconductor device with improved electrical characteristics can be obtained.

FIG. 2 is a sectional view showing a further improved semiconductor device. The die pad portion 11 and the inner leads 16 are shown in FIG.
(Lead for power supply or ground) is electrically connected by wire bonding (19) or by direct connection, and wire bonding is performed between the die pad portion 11 and the power supply or ground (ground) pad of the semiconductor chip. It is electrically connected by (20). Accordingly, the die pad portion 11 can be used as a power or ground plane. When the die pad portion 11 and the inner lead 16 are directly connected to each other, it is desirable that they are simultaneously connected when the lead frame is formed by stamping or etching.

FIGS. 3A to 3E show a manufacturing process of a semiconductor device according to still another embodiment. Differences from the embodiment of FIG. 1 will be described. In FIG. 3A, a plurality of relatively small holes 21 are provided at positions corresponding to the die pad portion 11 of the heat resistant resin film 14. Then, as in the case of FIG. 1, the resin film 14 is attached to the back surface of the lead frame 10. Note that FIG. 3B is a view seen from the back surface of the lead frame, and the hatched portion is the resin film 14. Next, as shown in FIG.
In the same manner as in the embodiment of FIG.
The two are bonded to each other, and the semiconductor chip 12 and the inner lead 16 of the lead frame are connected by wire bonding (15). If necessary, similarly to the embodiment of FIG. 2, electrically between the die pad portion 11 and the inner lead 16 (lead for power supply or ground) and between the die pad portion 11 and the semiconductor chip by wire bonding (20). Connecting. In addition, in FIG. 3C, the hatched portion indicates the resin film 14. Next, as shown in FIG. 3D, similarly to the embodiment shown in FIG. 1, the resin film 14 is hermetically sealed by the molding resin 18 so that the resin film 14 is exposed on the surface of the device, thereby completing the semiconductor device or the package. The resin film 14 is exposed on the outer surface of the package, and therefore,
The die pad portion 11 is also exposed on the back surface of the package through the small hole 21.

FIG. 3 (e) is a sectional view showing a state in which the semiconductor device thus manufactured is mounted on a substrate. In this embodiment, the solder balls 22 are embedded in the small holes 21 of the resin film 14 exposed on the surface of the semiconductor device. Then, these solder balls are aligned with the conductor portions 24 of the substrate 23, and at the same time, the outer leads 2 of the semiconductor device are
Solder paste 2 in which 5 is applied to the conductor portion 26 on the substrate 23
7, the semiconductor device is mounted on the substrate 23, and the necessary heating is performed to melt the solder balls 22 and the solder paste 27, thereby mounting the semiconductor device on the substrate 23 and electrically. Connection. Particularly, in this embodiment, not only the connection is made by the outer lead 25, but also the substrate 2 is connected via the solder ball 22.
The conductor portion 24 of No. 3 and the die pad portion 11 on the semiconductor device side are mutually coupled and electrically connected.

FIG. 4 is a plan view showing the plan view of FIG. 1D in more detail and in a wider range, and corresponds to the embodiment described in FIG. In FIG. 4, 10 is a lead frame, 10a is a support, and 10b is a die pad 11.
Is a dam bar for supporting and connecting a large number of inner leads 16 and outer leads 25, and 10 d is a hole for positioning a lead frame. The lead frame 10 is made of a metal strip material such as an iron-nickel alloy, a copper alloy, and pure nickel, and has a plate thickness of 70 μm to 250 μm. At least the tips of the inner leads 16 are made of silver, gold, or gold in order to enable wire bonding. It is plated with palladium. The heat-resistant insulating film 14 (hatched portion in the figure) attached to the back surface of the die pad 11 of the lead frame is made of polyimide and has a thickness of 30 μm to 200 μm, preferably 30 μm.
˜150 μm. Reference numeral 30 is an offset portion provided on the dam bar 11b to provide a step on the die pad 11. As a method of manufacturing the lead frame 10, a shape is removed by etching or pressing (stamping),
The order is silver plating, attachment of the insulating film 14, and offsetting to the die pad. In addition,
Manufacturing is performed by mounting the chip 12 on the lead frame 10 (using an organic adhesive. However, if the insulating film 12 is coated with an adhesive substance as described above, the adhesive is not necessary), wire bonding, resin sealing. Stop (epoxy resin), solder plating, lead shaping (dam bar removal, etc.) in that order.

Similar to FIG. 2B, FIG. 5 is a view of the lead frame as seen from the back side, showing it in more detail and in a wider range. The embodiment of FIG. 2 (or FIG. 5) is the same as the embodiment of FIG. 1 (or FIG. 4) except that the small holes 21 are provided in the insulating film 14 as described above. That is,
The insulating film 14 in which a plurality of small holes 21 are formed in a region corresponding to the die pad of the lead frame 10 is used. In addition, when assembling and manufacturing, insulating film 1
Solder balls are formed in the small holes 21 of No. 4, and lead shaping is performed so that the insulating film faces downward.

6 to 9 show an embodiment similar to the embodiment of FIG. 2 (FIG. 5) except that the die pad 11 is divided into a plurality of parts. 6 is a plan view corresponding to FIG. 4. The difference from FIG. 4 is that the die pad 11 of the lead frame 10 is electrically divided into a die pad portion 11a occupying a large area and several die pad portions 11b. It is a point that is divided so as to be insulated.

FIG. 7 is an enlarged view of a portion VII of FIG. In FIG. 7, a large die pad portion 11a,
The small die pad portion 11b is divided by a groove, and the small die pad portion 11b is formed integrally with a predetermined inner lead 11b. In this case, the large die pad portion 11a is used for grounding and the small die pad portion 1 is used.
1b is for power supply. As a result, the die pad portions 11a and 11b can be used as a ground plane and an electric plane. And tip 12
Signal signal pad 12a and signal inner lead 16
a is a wire 15, a ground pad 12b and a large die pad 11a of the chip 12 are a wire 19a, a large die pad 11a and an inner lead 16c for a ground are a wire 20a, and a power source of the chip 12 is a wire. Pad 12c
The small die pad 11b and the small die pad 11b are connected by a wire 19b by bonding. This allows the die pad 1
Chip 12 and inner lead 16 via 1a and 11b
An electrical connection between and becomes possible.

FIG. 8 is a view of the same portion as FIG. 7 viewed from the back side. In the insulating film 12, the small holes 2 are formed in the portions corresponding to the large die pad 11a and the small die pad 11b, respectively.
1a and 21b are formed. FIG. 9 is an enlarged plan view corresponding to FIG. 7. The difference from FIG. 7 is that the small die pad 1
1b is not directly connected to the inner lead but is formed in a separated form. In this case, in addition to the wire wiring shown in FIG. 7, the small die pad 11b and the inner lead 16b for power supply are connected by a wire 20b instead of the direct connection part.

FIGS. 10A to 10C show the die pad 11 of the lead frame 10 as in the embodiment of FIGS. 6 to 8.
7 shows a manufacturing process of an embodiment in which the large die pad 11a and the small die pad 11b are divided. FIG. 11 (a)
Is a small die pad 1 with the lead frame completed.
1b is directly connected to the power supply inner lead 11b.
Reference numeral 14 is an insulating film, and 21 is a small hole. Figure 11
(B) shows a state in which the chip 12 is mounted on the lead frame and connection is made by wire bonding. The insulating film 14 has a small hole 21a corresponding to the large die pad and a small hole 21b corresponding to the small die pad 11b. These small holes 21a and 21b are used for the chip 12 in FIG.
However, they may be arranged side by side in the lateral direction as shown in FIG. FIG. 11C shows a state of being mounted on the substrate 23 after being sealed with the mold resin 18. After the solder balls 22 are formed in the small holes 21 a and the small holes 21 b of the insulating film 14, the solder balls 22 are formed on the substrate 23. Will be implemented in. At that time, the outer lead 25, the large die pad 11a, and the small die pad 11b are electrically connected to the corresponding conductor portions of the substrate 23 through the solder portions.

The position and shape of the small die pad 11b to be separated can be variously selected depending on the arrangement of the connecting pads of the semiconductor chip 12. Further, the arrangement and size of the small holes 21a and 21b for solder connection are also determined by the position and shape of the connection portion (conductor pattern) 23 of the corresponding board. Although the embodiments have been described in detail with reference to the accompanying drawings of the present invention, the present invention is not limited to the above-mentioned embodiments, and various forms, modifications and corrections are made within the spirit and scope of the present invention. It should be noted that etc. are possible.

[0026]

As described above, according to the present invention, a semiconductor device which is excellent in electrical characteristics such as insulating properties or structural characteristics such as wiring form and which can achieve ultra-thinness. Or a package can be realized.

[Brief description of drawings]

1A to 1G show a manufacturing process of an embodiment of a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the semiconductor device of the present invention.

3A to 3E show manufacturing steps of a semiconductor device of still another embodiment.

FIG. 4 is a plan view corresponding to FIG. 1D, showing more detail and a wider range.

FIG. 5 is a diagram corresponding to FIG. 3B, showing a state viewed from the back surface of the lead frame in more detail and in a wider range.

FIG. 6 is a plan view corresponding to FIG. 4, showing an embodiment in which the die pad is divided.

7 is an enlarged plan view of a portion VII of FIG.

FIG. 8 is a view of the portion shown in FIG. 7 viewed from the back surface.

9 is a plan view showing still another embodiment corresponding to FIG. 7. FIG.

10A to 10C show manufacturing steps of the semiconductor device of the embodiment shown in FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Lead frame 11 ... Die pad 12 ... Semiconductor chip 13 ... Opening part 14 ... Insulating film 15, 19, 20 ... Wire 16 ... Inner lead 17 ... Offset part 18 ... Sealing resin 21 ... Small hole 22 ... Solder ball 23 ... Substrate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01L 23/50 N H01L 23/12 Z

Claims (6)

[Claims] 1. A die pad (11) of a lead frame (10) for mounting a semiconductor chip (12) is provided with an opening (13) larger than the semiconductor chip, and heat resistant insulation is provided so as to cover the opening. A semiconductor device comprising a film (14) attached to the back surface of a die pad, and the semiconductor chip mounted on an insulating film in the opening. 2. The lead frame (10) has a plurality of inner leads (16) and outer leads (25) connected to each inner lead, and a semiconductor chip (12).
And at least the inner lead (16) are connected by a wire (15), and the semiconductor chip (12),
A region including the inner lead (16) and the wire (15) is integrally sealed with a resin mold (18) to form a semiconductor package, and the insulating film (1
4. The semiconductor device according to claim 1, wherein 4) is exposed on the surface of the package. 3. An inner lead (16) used as a power source or a ground among a plurality of inner leads (16).
b, 16c) and the die pad (11), between the die pad (11) and the power supply or ground pad (12b, 12c) of the semiconductor chip (12), and other inner leads used for signals. A wire (1) is provided between the signal pad (12a) of the semiconductor chip and the signal pad (12a) of the semiconductor chip.
The semiconductor device according to claim 2, wherein the semiconductor device is electrically connected via (5, 19, 20). 4. The die pad (11) is divided into a plurality of pieces in a state of being electrically insulated from each other, one of the divided die pad portions (11b) serves as a power plane, and the other die pad portion (11a) is grounded. It is used as a power plane and the power plane is the inner lead (16
c) and the power supply pad (12c) of the semiconductor chip, and the grounding plane is electrically connected to the grounding inner lead (16b) and the grounding pad (12b) of the semiconductor chip, respectively. The semiconductor device according to claim 2. 5. A plane (11a, for power supply or ground)
11b) and the pads (12b, 12c) of the semiconductor chip are connected by wires (19a, 19b), and the planes (11a, 11b) for power or ground and the inner leads (16) are connected by wires or The semiconductor device according to claim 4, wherein the semiconductor devices are connected by an integral direct connection. 6. A package comprising a plurality of small holes (21) provided in a portion of an insulating film (14) overlapping the die pad (11) so that the die pad is exposed to the package surface through the small holes. Is mounted on the substrate (23), the die pad portion (11) and the conductor portion on the substrate (23) are joined by the solder (22) through the small holes (21). The mounting structure for a semiconductor device according to claim 2.