JPH02261696A - Ic module - Google Patents

Abstract

PURPOSE:To reduce the number of parts to be used or a falling process and to enhance humidity resistance and mass productivity by integrally forming a die pad to a conductive lead frame and bonding and fixing an IC chip to the die pad while sealing the IC chip and the lead frame by the same molding material excepting an external contact terminal. CONSTITUTION:A lead frame 21 integrally forms a die pad 25 for mounting an external contact terminal 22, internal wiring 23 and an IC chip 24. The external contact terminal 22 is formed in a protruding state by bending processing and a terminal is formed to the protruding surface thereof by plating treatment of Ni or Au. The fixing of the IC chip 24 to the die pad 25 is performed by the adhesion due to a die bond resin and the terminal of the IC chip 24 is connected to the internal wiring 23 through a bonding wire. The sealing of the entire contour of a module and the IC chip 24 is performed using the same molding material 27 according to an integral type transfer molding method. The IC module thus constituted is reduced in the number of parts and its manufacturing process and enhanced in its quality such as humidity resistance or mechanical strength by integral molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an IC module incorporating an IC chip such as a microprocessor or memory.

[Prior Art] In recent years, card-type media with built-in semiconductor devices have been rapidly becoming popular, and various forms have been devised for different uses and are being put into practical use. Until now, IC
Most of the media called cards are credit card-sized, and their development has been progressing based on worldwide standardization.

However, recently, there have been cases where IC cards with a built-in one-chip microcontroller are used for program commands in hand-held consumer devices such as cameras and video movies, as card-type media with a high degree of freedom that are not subject to standardization or standardization at all. has also started to be seen. This card has various sizes and shapes by making the additional functions independent from the main function and giving the user the ability to choose the functions.
The overall required items are summarized as follows.

(a) Be compact. (Minimize the space occupied by the built-in parts as much as possible) (b) Do not impair the design.

(c) Easy to handle. (Easy to insert and remove) (d) High reliability.

(e) It should be inexpensive.

Conventionally, the devices shown in FIGS. 9 and 10, for example, are known as devices that satisfy these requirements and quality.

Figure 0 shows the structure of the IC card 1 and the connector 2 built into the main device in a semi-perspective view. This is ensured by the contact of the terminal 4 when the card is inserted.

This type of connection method is generally called a card edge connection method, and has the advantage that there is little resistance when inserting and ejecting a card, and that it is easy to handle.

As shown in FIG. 1O, for example, the IC card 1 includes an IC module 5 provided with external contact terminals 3, and a card housing 7 provided with a window 6 for the contact terminals.
The opening of the housing 7 is closed by a design or picture plate 8.

The IC card 1 constructed in this manner is extremely compact, measuring several centimeters square.

Conventionally, as the IC module 5 used in such an IC card 1, those shown in FIGS. 11 and 12 are known.

In the case shown in FIG. 11, an external contact terminal 12 is provided on the protruding part of a printed circuit board 11 which has a partially protruded part formed on one side by cutting, and a Cu
Forming the wiring pattern 13 and the wiring pattern 13
and an external contact terminal 13 are connected via a through hole 14. Then, an IC chip 1 is placed on the other side of the printed circuit board 11.
5 is directly mounted using an adhesive such as a die-bonding resin, the IC chip 15 and the wiring pattern 13 are connected by a bonding wire 16, and a dam frame for resin sealing is provided around the other side of the printed circuit board 11. 17 is provided, and the inside of the frame 17 is filled with a sealing resin 18.

(Botting mold method) In addition, the method shown in FIG. 12 does not use the resin sealing dam frame 17, but instead is placed in a mold with a predetermined external outline, and a highly fluid sealing resin 19 is applied. It is formed by low-pressure injection. (Partial Transfer Molding Method) [Problems to be Solved by the Invention] However, conventional IC modules have the following problems.

(a) The cost of printed circuit board materials with excellent dimensional accuracy, dimensional stability, and durability increases, and mass production is also lacking.

(b) Since a protrusion is provided for the external contact terminal, it is difficult to control the accuracy of machining (cutting). In addition, it is difficult to employ a continuous processing process, resulting in poor mass production.

(C) The thickness accuracy of the module is restricted by the thickness accuracy of the base substrate, making it difficult to manage the thickness accuracy.

(d) Moisture resistance decreases if the adhesion between the substrate surface and the resin surface deteriorates, or if there is insufficient resin thickness or insufficient packing density above the IC chip.

Therefore, the present invention has low cost, excellent mass productivity, easy quality control, and can improve quality.
Furthermore, the present invention aims to provide an IC module with excellent moisture resistance.

[Means for Solving the Problems] In an IC card module in which external contact terminals are formed to protrude, the external contact terminals, internal wiring, and a die pad for mounting the IC chip are integrally formed by a conductive lead frame, An IC chip is adhesively fixed to a die pad, and the 1C chip and lead frame are sealed with the same molding material except for external contact terminals.

[Function] In the present invention, the external contact terminals, internal wiring, and the die pad for mounting the IC chip are integrally formed by the lead frame, so the number of parts used and the processing steps are reduced. Furthermore, since the IC chip and the lead frame are sealed with the same molding material except for the external terminals, it is possible to improve moisture resistance and mass productivity.

[Example] In FIG. 1, 21 is a lead frame, and this lead frame 21 has external contact terminals 22, internal wiring 23, and an IC.
A die pad 25 on which a chip 24 is mounted is integrally formed.

The external contact terminal 22 is formed into a convex shape by bending, and a terminal is formed on the protruding surface by a plating process such as NIS Au. The IC chip 24 is fixed to the die pad 25 by adhesion using die bond resin. Further, the terminals of the IC chip 24 and the internal wiring 23 are connected via bonding wires 26.

The outline of the entire module and the IC chip 24 are sealed by using the same molding material 27 and using an integrated transfer molding method.

Note that the mounting method for the IC chip 24 is not limited to the wire bonding method, but may also be the TAB method in order to limit the mounting height and reduce the thickness of the module, or the flip-button knob method using bump formation. may be adopted.

Next, a method for manufacturing the lead frame 21 will be described. Here, an example of a method for forming grooves by etching will be described. Other methods include punching with a press die and laser drawing.

A conductive metal plate (stainless steel material such as 4270I is preferable) with a relatively small coefficient of thermal expansion is coated with a photosensitive resist film, and after exposing the pattern of the film original plate, the unexposed areas of the resist are washed with water. do. This metal plate is exposed to an etching solution such as ferrous chloride to dissolve unnecessary parts, and a master plate with a predetermined pattern is completed.

Furthermore, a resist solution for plating is coated on the designated areas.

FIG. 2 shows a portion of the lead frame that has been etched. In the figure, 31 is a half-etched cutting groove, 32 is a bending groove that is also half-etched, 33 is an Au plating part of the external contact terminal 22, 34 is an Au plating part for wire bonding, and 35 is an IC chip. The dieper throat (base), 36 is a pin hole for placement.

Next, as shown in Fig. 3, press processing is performed using a bending die to form a convex shape for the terminal portion and to form a pedestal for the die pad, and then a predetermined plating process is performed in a plating treatment tank, as shown in Fig. 4. A lead frame base material 37 is completed.

Next, the mounting and molding method will be described.

Although not shown, a lead frame in which the IC chip 38 is bonded to the die pad 35 and wire-bonded is inserted into a mold having the outer shape of the module, and a resin having good fluidity and a small thermal fluctuation rate is press-fitted.

At this time, in order to improve resin wrapping and filling properties, it is desirable to install resin gates at two locations on a pair of side surfaces perpendicular to the external terminal row, and install air vents at two locations on the bridge side surface of the lead frame. .

After this resin injection and cooling, a prescribed aging is performed and the fifth
Transfer molding as shown in the figures and FIG. 6 is completed.

If the cutting groove 31 is cut, the IC shown in FIG.
The module will be molded.

The IC module constructed in this way has a considerable reduction in the number of parts and its processing steps, and product quality can be easily controlled.

In addition, costs such as parts costs and processing costs are significantly reduced, and mass production effects can be achieved by reducing man-hours.

In addition, the integral molding improves quality such as moisture resistance and mechanical strength. In addition, the stability and level of dimensional accuracy can be improved.

Furthermore, since the convex terminals are formed using a lead frame, there is no need for machining, and a continuous process can be used.

Note that in order to prevent thermal shrinkage after aging and cracks due to residual stress in the resin due to repeated changes in temperature, it is desirable to make the resin pressure in the vertical direction as equal as possible. Also, the shorter the bonding wire is, the easier it is to prevent defects such as disconnection.

In the above embodiment, the IC chip 24 is bonded and fixed to the die pad 25 with the IC chip 24 facing upward, but the IC chip 24 is not necessarily limited to this, and as shown in FIG. It may be something that has been done.

Further, in the embodiment described above, the die pad 25 is bent slightly and the IC chip 24 is fixed by adhesive, but the invention is not necessarily limited to this, and as shown in FIG. It may be fixed with adhesive.

[Effects of the Invention] As detailed above, according to the present invention, the external contact terminals, internal wiring, and die pad are integrally formed on the lead frame,
In addition, since the IC chip and lead frame that are adhesively fixed to the die pad are sealed with the same molding material, the cost is low and mass production is excellent, and quality control is easy and quality can be improved. I with excellent moisture resistance
C module can be provided.

[Brief explanation of drawings]

1 to 6 show one embodiment of the present invention, in which FIG. 1 is a sectional view, FIGS. 2 to 6 are diagrams for explaining the processing steps, and FIGS. 7 and 8. 9 is a sectional view showing another embodiment of the present invention, FIG. 9 is a semi-perspective view showing the structure of an IC card and a connector built into the main device, FIG. 10 is an exploded perspective view of the IC card, FIGS. FIG. 12 is a sectional view showing a conventional example. 21...Lead frame 22...External contact terminal 2
3... Internal wiring 24... IC chip 25.
...Die pad 27...Mold material. Applicant's Representative Patent Attorney Takehiko SuzueFigure 1Figure 9Figure 2Figure 2Figure Figure Figure

Claims (1)

[Claims] In an IC card module formed with a protruding external contact terminal, the external contact terminal, internal wiring and I
A die pad for mounting the C chip was integrally formed with a conductive lead frame, an IC chip was adhesively fixed to the die pad, and the IC chip and the lead frame were sealed with the same molding material except for the external contact terminals. An IC module characterized by: