JPH06216277A - Semiconductor device and ic card comprising the same - Google Patents

Abstract

(57) [Abstract] [Purpose] Preventing warpage of the package in semiconductor devices. [Structure] The inner lead 7 of the metal lead 3 is connected to the upper surface of the semiconductor chip 5 via an adhesive 10, and the electrode of the semiconductor chip 5 and the inner lead 7 are connected by a wire 9, and the outer of the lead 3 is connected. In the semiconductor device, a portion excluding the leads 4 is sealed with a package 2 made of resin, and a dummy tab 11 made of metal is adhered to the lower surface of the semiconductor chip 5 via an adhesive 10. The resin forming the package 2 as compared with the metal lead 3 is
When the semiconductor chip 5 has a large thermal expansion coefficient and the leads 3 are bonded to one surface of the semiconductor chip 5, the package may warp due to thermal stress. However, the dummy tab 11 made of metal is used.
Is bonded to the other surface of the semiconductor chip 5, the material in the thickness direction of the package is balanced, and thus the warp of the package 2 does not occur.

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 more particularly to a semiconductor device having a structure in which an inner lead portion of a metal lead is connected to one surface of a semiconductor chip and electrodes of the semiconductor chip are electrically connected to the inner lead. For example, the present invention relates to a technique effectively applied to a semiconductor device having a LOC (lead on chip) structure.

[0002]

2. Description of the Related Art As one of package structures of a semiconductor device, an inner lead of a metal lead frame is adhered to one surface of a semiconductor chip, electrodes of the inner lead semiconductor chip are connected by a conductive wire, and LOC where the whole body except the outer leads is sealed with a resin package
The structure is known. For the semiconductor device of LOC structure, "Nikkei Microdevice" 1989 issued by Nikkei BP.
September issue, September 1, issue, P109-P114. This document uses a leadframe with a polyimide film attached instead of a die pad. 4
ZI for MDRAM (Dynamic Random Access Memory)
P (Zig-zag Inline Package) is disclosed. Bonding of the chip and the lead frame is done by a polyimide film with adhesive on both sides. As the adhesive, acrylic, silicone, polyimide, or polyether amide imide is used. The lead frame is made of Fe-50Ni (coefficient of thermal expansion: 10 × 1).
0 ^-6 / ° C) and Fe-42Ni (thermal expansion coefficient: 5.3 ×
10 ^-6 / ° C) is used. The thermal expansion coefficient of the resin forming the package is 14 × 10 ⁻⁶ / ° C.

On the other hand, "Nikkei Microdevice" issued by Nikkei BP, February 1991, issued February 1, 1981, P89-
P97 describes a 16MDRAM using a LOC structure. Further, in this document, a conventional structure in which a chip is mounted on a die pad, a COL (chip on lead) structure in which a chip is mounted on a lead via an insulating tape, and a lead is fixed on the chip via an insulating tape. To L
The OC structure is illustrated, and its advantages and disadvantages are compared. Further, this document illustrates the problem to be solved by the LOC structure, and cites the characteristic variation due to thermal stress as one of the problems to be solved. For assembly, "For die attachment, attach the polyimide tape with adhesive applied on both sides to the lead frame and then attach the chip (Fig. 7)."
The chip is moved to the bonding head with the chip control stage, and the lead frame with tape is heated and pressure bonded (Fig. 8). At this time, use tape with adhesive on both sides. The stage doubles as a heater. The lead frame is purchased with the tape attached. ". Regarding the transfer mold, it is described that "the mold flow simulation is performed so that voids do not occur during transfer molding, and the balance of resin flow above and below the chip is determined (FIG. 10)". The polyimide tape used has a thickness of 50 μm.

On the other hand, as one of the cards for storing and reading various information in recent years, an IC incorporating an integrated circuit (IC) or the like.
The card is being used. Regarding the IC card, for example, “Nikkei Microdevice” March 1988 issue by Nikkei McGraw-Hill, March 1, 1988 issue, P5
6 to P62. As one of the structures of an IC card, an IC chip such as an LSI (Large Scale Integrated Circuit) is incorporated into a wiring substrate called a module base material, and the IC chip portion is molded by transfer molding to form an IC card module. None, this I
A structure in which a C card module is incorporated in a card base material is known.

[Electronic Materials] 199 issued by the Industrial Research Board
The December 0 issue, issued December 1, the same year, P27 to P29 describe the mounting technology of IC cards. This document describes TSOP as a method of mounting a memory chip.
How to use (Thin Small Outline Package), TAB
(Tape Automated Bonding) method, COB (Chip
It is stated that there is a method of using the On Board). This document also discloses a memory card incorporating TSOP and the like.

[0006]

The LOC structure is such that metal leads are attached to the upper surface of a flat semiconductor chip, and the entire upper and lower surfaces are sealed with a package made of resin. The resin forming the package has a larger coefficient of thermal expansion than the leads, as can be seen from the above-mentioned literature.
The coefficient of thermal expansion in the case of a metal lead according to the above-mentioned document is
5.3 × 10 ^-6 / ° C (Fe-42Ni), or 1
It becomes 0 × 10 ^-6 / ° C (Fe-50Ni), and the thermal expansion coefficient of the resin forming the package becomes 14 × 10 ^-6 / ° C. By the way, it has been found that in the LOC structure, the package sometimes warps after transfer molding due to a difference in thermal expansion coefficient between the lead and the resin and a difference in upper and lower resin thicknesses. This warpage extends to about 40 to 100 μm in a package having a length of several cm. It has also been found that in a semiconductor device in which the package warps significantly, the semiconductor chip inside the package is damaged by cracks.

On the other hand, since the IC card is used while being carried, it is required to have sufficient strength against bending stress.

An object of the present invention is to provide a semiconductor device whose package is hard to warp.

Another object of the present invention is an IC having high bending strength.
Is to provide a card. The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0010]

The outline of the representative ones of the inventions disclosed in the present application will be briefly described as follows. That is, the semiconductor device of the present invention is
The inner lead portion of the metal lead is connected to the upper surface of the semiconductor chip on which the electrodes are formed via an insulating double-sided adhesive tape. The tips of the inner leads are electrically connected to the electrodes of the semiconductor chip via wires.
Further, a metal dummy tab made of the same material as the lead frame is bonded to the lower surface of the semiconductor chip via a double-sided adhesive tape. The dummy tab, the semiconductor chip, the inner lead and the wire are sealed with a package made of resin, and the outer lead of the lead projects outside the package. A resin having substantially the same thickness is provided outside the inner lead and the dummy tab.

A semiconductor device according to another embodiment of the present invention is
Connect the inner lead part of the metal lead to the upper surface of the semiconductor chip electrode with an insulating double-sided adhesive tape, connect the semiconductor chip electrode and the inner lead with a wire, and connect the outer lead lead. It has a structure in which a portion excluding it is sealed with a package made of resin, and a dummy tab made of the same material as that of the lead frame is bonded to the lower surface of the semiconductor chip, one surface of which is exposed from the package. A resin having substantially the same thickness is provided outside the inner lead and the dummy tab.

The IC card according to the present invention is composed of a card base material composed of a center core and oversheets attached to both surfaces of the center core. An accommodation recess is provided in a part of the card base material, and the IC card module is fitted into the accommodation recess.
The IC card module is composed of a module substrate including a substrate and a semiconductor device mounted on the inner surface of the module substrate. The module substrate has a contact electrode on the exposed outer surface. In the semiconductor device, an inner lead portion of a metal lead is connected to an upper surface of a semiconductor chip on which an electrode is formed via an insulating double-sided adhesive tape, and an electrode of the semiconductor chip and an inner lead are connected by a wire, and It has a structure in which the parts of the leads excluding the outer leads are sealed with a package made of resin.
In addition, a dummy tab made of metal and made of the same material as the lead frame is bonded to the lower surface of the semiconductor chip.

[0013]

According to the above means, in the semiconductor device of the present invention, the inner lead is attached to the upper surface of the semiconductor chip, and the dummy tab made of the same material as the inner lead is attached to the lower surface of the semiconductor chip. Since the resin having substantially the same thickness is provided on the outer sides of the inner lead and the dummy tab, the warping of the package due to thermal stress does not occur due to the material balance in the thickness direction of the package. Therefore, deterioration such as cracking of the semiconductor chip is eliminated.

A semiconductor device according to another embodiment of the present invention, that is, a semiconductor device having a structure in which one surface of a dummy tab is exposed to the outside of the package prevents the package from warping due to the dummy tab and the dummy tab functions as a heat sink. Since this also works, the thermal characteristics of the semiconductor device are improved.

In the IC card of the present invention, since the semiconductor device incorporated in the card base has a metal dummy tab arranged in the package, the dummy tab acts as a reinforcing member, so that the card base The rigidity is increased, and the bending strength of the IC card can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention, FIG. 2 is a schematic view showing an assembled state of the semiconductor device according to an embodiment of the present invention, and FIG. 3 is a wire-bonded lead in the assembly of the semiconductor device. FIG. 4 is a sectional view showing a frame, FIG. 4 is a sectional view showing a lead frame similarly molded in assembling a semiconductor device, and FIG. 5 is a sectional view showing a part of an IC card according to the present invention.

The semiconductor device 1 of the present invention is shown in FIG.
As shown in, the resin (coefficient of thermal expansion: 14 × 10 ⁻⁶ / °
A plurality of leads 3 are projected from the peripheral surface of the package 2 formed in C). The lead 3 is made of metal,
For example, Fe-42Ni (coefficient of thermal expansion: 5.3 × 10 ⁻⁶
/ ° C), and the outer portion (outer lead 4) of the package 2 is a gull wing type suitable for surface mounting. A semiconductor chip 5 having an LSI (Large Scale Integrated Circuit) formed therein is provided in the package 2. Although not shown, electrodes are provided on the upper surface of the semiconductor chip 5. The inner lead 7 portion of the lead 3 is attached to the upper surface of the semiconductor chip 5 via an insulating adhesive body 6. The adhesive body 6 is made of, for example, a polyimide film having a thickness of 80 μm and having an insulating adhesive on both sides. The inner end of the inner lead 7 and the electrode (not shown) of the semiconductor chip 5 are electrically connected by a conductive wire 9.

On the other hand, this is one of the features of the present invention. On the lower surface of the semiconductor chip 5, the insulating adhesive 1
A plate-shaped dummy tab 11 is attached via 0. Like the adhesive body 6, the adhesive body 10 is made of a polyimide film having an insulating adhesive on both sides and having a thickness of 80 μm. The dummy tab 11 is made of the same material as the lead 3 and has the same thickness. A resin having the same thickness is provided on the upper side of the inner lead 7 and the lower side of the dummy tab 11. Here, an example of dimensions of each part will be described. The lead 3 and the dummy tab 11 each have a thickness of 125 μm, the semiconductor chip 5 has a thickness of 280 μm, the resin on the inner lead 7 and the dummy tab 11 has a thickness of 195 μm, and the semiconductor chip 5 has the inner lead 7 and the dummy tab 11 respectively. The thickness of the bonded body 6 to be bonded is 80 μm, and the thickness of the package 2 is about 1 μm.
mm. And even the surface mount height is 1.
It is designed to be about 2 mm. As a result, the arrangement of the materials in the height direction of the package 2 is vertically symmetrical with respect to the semiconductor chip 5, and the thermal stress balance is maintained. Therefore, the semiconductor chip 5 does not warp due to the imbalance of thermal stress when the resin is thermally contracted during the formation of the package 2. Further, since the dummy tab 11 serves as a strength member, the strength of the package 2 also increases.

Next, a method of manufacturing such a semiconductor device 1 will be described with reference to FIGS. First, the semiconductor chip 5, the dummy tab 11, and the lead frame 15 are prepared. The lead frame 15 is a frame on which the leads 3 are formed, and is made of Fe- having a thickness of 125 μm.
It is made of 42Ni. The adhesive 6 is attached to the lower surface of the inner lead 7 of the lead frame 15. The adhesive 10 is also attached to the upper surface of the dummy tab 11. The dummy tab 11 is placed on a table (not shown), then the semiconductor chip 5 is positioned and stacked, and the lead frame 15 is positioned and stacked on the semiconductor chip 5. Then, these three members are heated (300 ° C.) and pressurized to be integrated as shown in FIG.

Next, as shown in FIG. 3, the electrodes (not shown) of the semiconductor chip 5 and the tip portions of the inner leads 7 are electrically connected by the conductive wires 9.

Next, as shown in FIG. 4, the lead frame 15 is molded by a transfer molding device (not shown). In this mold, since the height of the mold space above the inner lead 7 is the same as the height of the mold space below the dummy tab 11, the resin that flows in from one end side flows evenly into the upper and lower mold spaces, and bubbles (voids) inside. ) Is not formed, a package excellent in moisture resistance is formed. By this molding, the dummy tab 11, the semiconductor chip 5, the inner leads 7, the wires 9 and the like are sealed by the package 2. Therefore, the gull wing type semiconductor device 1 as shown in FIG. 1 is manufactured by cutting and removing the unnecessary lead frame portion and molding the outer lead 4 protruding from the package 2.

In such a semiconductor device 1, since the package strength is increased due to the presence of the dummy tab, I
When incorporated in a C card, it increases the bending strength of the IC card. FIG. 5 is a sectional view showing a part of the IC card 20 according to the present invention. The IC card 20 includes a plate-shaped center core 21 and an oversheet 2 that covers both sides of the center core 21.
It is composed of a card substrate 23 composed of 2 and.
In addition, a storage recess 24 formed of a two-step recess is provided on one surface of the card base material 23, and the storage recess 24 is also provided.
An IC card module 25 is fitted in the.
The IC card module 25 is composed of a module board 26 made of a rectangular wiring board and the semiconductor device 1 mounted on the inner surface of the module board 26. The semiconductor device 1 is mounted by electrically connecting the leads 3 to the wiring layer 27 on the inner surface of the module substrate 26. A contact electrode (not shown) is provided on the exposed outer surface of the module substrate 26.
The inner peripheral edge portion of the module substrate 26 is bonded to the groove bottom of the shallow recess 29. As a result, the IC card module 25 is attached to the card base material 23. The semiconductor device 1 is a dummy tab 11 according to the present invention.
It has a structure having. Therefore, the dummy tab 1
Since 1 serves as the reinforcing member for the package 2 and the reinforcing member for the card base material 23, the strength of the IC card 20 against bending stress is improved.

[0023]

(1) The semiconductor device of the present invention has a structure in which the inner lead is attached to one surface of the semiconductor chip, and the dummy tab made of the same material and having the same thickness as the inner lead is attached to the other surface. Moreover, since the resin of the same thickness is arranged on the inner lead and under the dummy tab, the material arrangement is symmetrical with respect to the semiconductor chip in the thickness direction of the package,
Since the thermal stress balance is maintained, the effect that the warpage phenomenon of the package does not occur can be obtained.

(2) Because of the above (1), the semiconductor device of the present invention does not warp the package.
The semiconductor chip is not cracked and the reliability is improved.

(3) According to the above (1) and (2), in the semiconductor device of the present invention, the dummy tab is attached to the lower surface of the semiconductor chip. Since this dummy tab acts as a strength member, the package strength is increased. The effect that is improved is obtained.

(4) In the IC card of the present invention, since the semiconductor device having the dummy tab in the package is incorporated, the dummy tab serves as a strength member of the package and the card base material, so that the IC is strong against bending stress. The effect of becoming a card is obtained.

(5) Due to the above (1) to (4), according to the present invention, it is possible to provide a synergistic effect that it is possible to provide a semiconductor device in which the package is difficult to warp and an IC card having high bending strength.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example,
If the lower surface of the dummy tab 11 is exposed to the outside of the package 2 as shown in FIG.
Since 1 acts as a heat sink, the thermal characteristics of the semiconductor device 1 are improved. Further, in this structure, since the resin is not provided on the lower surface side of the dummy tab 11, the thickness of the package can be further reduced.

In the above description, the invention mainly made by the present inventor is applied to the manufacturing technology of the gull-wing type resin-encapsulated semiconductor device and the IC card incorporating the semiconductor device, which is the field of application of the invention. However, the present invention is not limited thereto. INDUSTRIAL APPLICABILITY The present invention can be applied at least to the manufacture of a resin-sealed semiconductor device and a thin electronic device incorporating the semiconductor device.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an assembled state of a semiconductor device according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a lead frame wire-bonded in an assembled state of a semiconductor device according to an exemplary embodiment of the present invention.

FIG. 4 is a sectional view showing a lead frame molded in an assembled state of a semiconductor device according to an embodiment of the present invention.

FIG. 5 is a sectional view showing a part of the IC card of the present invention.

FIG. 6 is a sectional view showing a semiconductor device according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2 ... Package, 3 ... Lead, 4 ... Outer lead, 5 ... Semiconductor chip, 6 ... Adhesive body, 7 ... Inner lead, 9 ... Wire, 10 ... Adhesive body, 11 ... Dummy tab, 15 ... Lead frame , 20 ... IC card, 2
DESCRIPTION OF SYMBOLS 1 ... Center core, 22 ... Oversheet, 23 ... Card base material, 24 ... Housing depression, 25 ... IC card module, 26 ... Module substrate, 27 ... Wiring layer, 29 ... Shallow depression.

Claims (5)

[Claims] 1. A package made of resin, and a plurality of metal leads extending inside and outside the package,
A semiconductor device comprising: a semiconductor chip connected to one surface of a plurality of lead parts in the package via an adhesive; and a connecting means for electrically connecting the electrodes of the semiconductor chip to the leads. A semiconductor device characterized in that a dummy tab made of metal is bonded to the surface of the chip on which the leads do not extend. 2. The lead is connected to the upper surface of the semiconductor chip on which the electrode is formed, the lead and the electrode of the semiconductor chip are connected by a conductive wire, and a dummy tab is bonded to the lower surface of the semiconductor chip. The semiconductor device according to claim 1, wherein the semiconductor device comprises: 3. The semiconductor device according to claim 1, wherein the dummy tab comprises a bimetal with a semiconductor chip and a lead, and has a size configuration that does not warp due to heat. 4. The semiconductor device according to claim 1, wherein one surface of the dummy tab is exposed from the package. 5. An IC card incorporating a semiconductor device, comprising a package made of resin, a plurality of metal leads extending inside and outside the package, and a plurality of lead portions inside the package. A semiconductor chip connected to one surface via an adhesive, a connecting means for electrically connecting the electrodes of the semiconductor chip and the leads, and a metal dummy tab bonded to the surface of the semiconductor chip on which the leads do not extend. An IC card having a built-in semiconductor device including and.