JP3030879B2 - IC memory card - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC memory card containing a large number of memory LSI chips.

[0002]

2. Description of the Related Art An IC memory card is widely used as a portable information storage device incorporating a memory LSI such as a RAM and a ROM. In recent years, with the expansion of its use,
An IC memory card having a large storage capacity, that is, a large capacity has been strongly demanded. In such a large-capacity IC memory card, a large number of memory LSIs are required.
Must be densely mounted on a printed wiring board having a fixed area.

As a high-density mounting method of a memory LSI, there is a method of bonding conductor leads to electrodes of a bare chip of the memory LSI by a so-called film carrier method and mounting the memory LSI chips on a printed wiring board in a plane. Was considered effective. Referring to the drawings, a number of memory LSIs will be described by a film carrier method.
The structure of a conventional IC memory card in which a chip is mounted on a printed wiring board will be described.

FIG. 5A is a partial sectional view showing a conventional IC memory card, and FIG. 5B is a partial plan view of the same. In FIGS. 5A and 5B, reference numeral 31 denotes a case that houses the printed wiring board 32. Conductive wiring 33 is formed on the printed wiring board 32. 34,3
Reference numeral 4 'denotes a memory LSI chip which is arranged on the printed wiring board 32 in a planar manner. Also, the memory LSI chips 34 and 3
The electrode surfaces 34a and 34'a of the 4 'both face in the same direction, and are arranged in a direction not facing the printed wiring board 32 in this row. Memory LSI chips 34, 34 '
Are connected to the respective electrodes 35, 35 'via metal protrusions 36, 36' by a film carrier method.
7, 37 'are joined to one end 37a, 37'a, and the other ends 37b, 37'b of the conductor leads 37, 37' are joined to the conductor wiring 33 of the printed wiring board 32. Since the bare chip is used as described above, the area occupied by the memory LSI on the printed wiring board is relatively small.

[0005]

However, in the above-mentioned conventional configuration, since the memory LSI chips are arranged in a plane on the printed wiring board, the area occupied by the memory LSI chips increases as the number of memory LSI chips increases. Therefore, a memory LS that can be mounted on a printed wiring board having a certain area
The number of I chips was naturally limited. Also, since the electrode surface of each memory LSI chip is arranged in the same direction with respect to the surface of the printed wiring board, the conductor wiring of the printed wiring board that connects between the conductor leads bonded to the common electrode of each memory LSI chip However, there is a problem that the signal transmission speed is reduced because the wiring length increases and the wiring space increases.

The present invention solves the above-mentioned conventional problems, and realizes a large capacity by mounting a large number of memory LSI chips on a printed wiring board having a fixed area, and reduces a signal space by reducing a wiring space. To realize high-speed transmission, to prevent deformation of conductor leads, etc. to facilitate the assembling process, and to facilitate the production of film carriers to realize a low-cost and highly reliable IC memory card. With the goal.

[0007]

In order to achieve the above object, an IC memory card according to the present invention has one end of a conductor lead joined to an electrode of a memory LSI chip by a film carrier method, and an intermediate portion of the conductor lead and other parts. The ends are connected by an insulating film, a plurality of the memory LSI chips are stacked on the printed wiring board in a direction in which the arrangement of the electrodes is the same, and between the middle part and the other end of the conductor lead connected to the common electrode. Is partially overlapped and joined to the conductor wiring of the printed wiring board, and further, the electrode surface of the memory LSI chip is stacked in a direction facing the printed wiring board (hereinafter referred to as a face-down set). A pair of layers (hereinafter referred to as a face-up group) stacked in a direction in which the surface does not face the printed wiring board, and a pair of conductor leads of the same stage in both sets, Parts that are identical with the structure of the length between.

[0008]

With this configuration, a large capacity is realized by mounting a large number of memory LSI chips on a printed wiring board, the conductor leads of the common electrode between the stacked chips are directly joined, and a face-down set is formed. By arranging the face-up pair adjacent to each other, the wiring space is reduced and the signal transmission is speeded up.Furthermore, the connection between the conductor lead and the conductor wiring is facilitated, and both sets are placed in the same stage. Since film carriers having the same shape can be used, the production of the film carrier is facilitated, and the cost can be reduced.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of an IC memory card according to an embodiment of the present invention, FIG. 2 is a block diagram of an electric circuit, FIG. 3 is a partial sectional view, and FIG. FIG. 1 to 4, reference numeral 1 denotes a case in which the printed wiring board 2 is housed. The printed wiring board 2 includes a memory circuit section 3, a control circuit section 4, and an external interface circuit section 5. The memory circuit unit 3 includes a plurality of memory LSI chips 6, 7, and the like.
A large number of stacked RAM chips of the same type are mounted on the printed wiring board 2. The control circuit section 4 includes a decoder IC 8 and performs chip selection by an address signal, backup control by power supply switching, and the like. The external interface circuit section 5 includes a connection connector 9 and the like. The connection connector 9 is connected to a connection section (not shown) attached to another device or apparatus, and supplies power to the printed wiring board 2. Send and receive signals. Reference numeral 10 denotes a battery for backing up the memory circuit unit 3, which is stored in the case 1 using a coin-type lithium battery or the like. The battery 10 supplies backup power to the memory circuit unit 3 when power is not supplied from the connector 9.

Next, a memory L which is a face-up set
The configuration of the stacked state of the SI chips 6, 6 'and the memory LSI chips 7, 7' which are a face-down set will be described. 11 and 12 are memory LSI chips 6, respectively.
7, one end portions 15 a, 15 a, of the conductor leads 15, 16 via the metal projections 13, 14 by a film carrier method.
16a are respectively joined. Reference numerals 17 and 18 denote other electrodes of the memory LSI chips 6 and 7, respectively, and one ends 19a and 20a of the conductor leads 19 and 20 are joined in a similar manner. Intermediate portions 15b and 19 of conductor leads
b, 16b and 20b are insulating films 21 and 22, respectively.
And the other ends 15c and 19c, 16 of the conductor leads.
c and 20c are connected by insulating films 23 and 24, respectively. The length from the middle part 15b to the other end 15c of the conductor lead is the same as the length from the middle part 16b to the other end 16c of the conductor lead. The same applies to the conductor leads 19 and 20. Reference numerals 25 and 26 denote insulating members made of resin, which serve to protect the electrodes 11 and the like. The above configuration is based on the memory LSI chip 6 ',
The same applies to 7 '.

Next, the state of electrical connection of the conductor leads 15 and 16 to the printed wiring board 2 will be described. Since the electrodes 11, 11 ', 12, 12' are common electrodes of the memory LSI chips 6, 7, the conductor leads 15, 16
Are connected to the same conductor wiring 27 of the printed wiring board 2 together with the first-stage conductor leads 15 ′ and 16 ′. Since the electrodes 17 and 18 are also common electrodes of the memory LSI chips 6 and 7, the conductor leads 19 and 20 are connected to the conductor wiring 28 of the printed wiring board 2 together with the first-layer conductor leads (not shown). ing. Although not shown, the conductor leads connected to the non-common electrodes of the memory LSI chips 6, 6 ', 7, 7' are respectively connected to different conductor wirings different from each other.

Next, the state of joining the conductor leads 15 and 16 to the conductor wirings 27 and 28 will be described. The conductor leads 15, 15 'are soldered to the conductor wiring 27 by partially overlapping the respective other ends 15c, 15c' from the respective intermediate portions 15b, 15'b. The conductor leads 16, 16 'are also connected to the respective intermediate portions 16b, 1
From 6'b, the other end portions 16c and 16'c are partially overlapped and soldered to the conductor wiring 27. Similarly, the conductor leads 19 and 20 are soldered to the conductor wiring 28. Then, with respect to the first-layer conductor leads 15 'and 16',
The length from 5'b to the other end 15'c and the middle 16 '
The length from b to the other end 16'c is the same. As described above, the second-stage conductor leads 15 and 16 have the same configuration.

As described above, according to this embodiment, the memory L
By stacking a plurality of SI chips 6 and the like and mounting them on the printed wiring board 2, the area occupied by the memory LSI chips 6 and the like is greatly reduced, and a large-capacity IC memory card can be realized. Also, the memory LSI chips 6, 6 'and 7, 7' are made into a face-up set and a face-down set, respectively, and the conductor leads 15, 15 'connected to the common electrodes 11, 11' and the like are partially overlapped. An IC memory card with a high signal transmission speed can be realized by joining to the conductor wiring and arranging the same side of these sets adjacent to each other to shorten the distance between the conductor wirings 27 and 28. Further, the middle portions 15b and 19b of the conductor leads are connected by the insulating film 21, and the other end portions 15c and 15c of the conductor leads are connected.
Since the conductor leads 19 and 19c are connected by the insulating film 23, the conductor leads 15 and 19 are not likely to come into contact with each other due to deformation or misalignment, so that soldering is facilitated. By making the length and the length from the middle part 16b to the other end part 16c of the conductor lead the same, the same shape of the film carrier is used in the same stage of the face-up group and the face-down group. A low-cost IC memory card that is easy to assemble and easy to manufacture a film carrier can be realized.

[0015]

According to the IC memory card of the present invention, one end of the conductor lead is joined to the electrode of the memory LSI chip by a film carrier method, and the middle and the other end of the conductor lead are connected by an insulating film. A plurality of LSI chips are stacked on the printed wiring board, and a portion between the middle part and the other end of the conductor lead connected to the common electrode is partially overlapped and joined to the conductor wiring of the printed wiring board. A film carrier having a face-up set and a face-down set, having the same length between the middle part and the other end of the conductor lead of the same step in both sets, and having the same shape in the same step in both sets Is a configuration that can be used. Accordingly, the present invention realizes a large capacity by mounting a large number of memory LSI chips on a printed wiring board, realizes a high-speed signal transmission by reducing a wiring space, and furthermore, handles a conductor lead and a conductor lead. In addition, the present invention has an excellent effect of facilitating the joining of the wiring and the conductor wiring, and also facilitating the production of the film carrier and realizing the cost reduction.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of an IC memory card according to an embodiment of the present invention.

FIG. 2 is a block diagram of an electric circuit of the memory card.

FIG. 3 is a partial cross-sectional view of the memory card.

FIG. 4 is a partial plan view of the memory card.

FIG. 5A is a partial sectional view of a conventional IC memory card. FIG. 5B is a partial plan view of the memory card.

[Explanation of symbols]

 2 Printed wiring board 6,7 Memory LSI chip 11,12 Common electrode 15,16 Conductor lead 15a, 16a One end of conductor lead 15b, 16b Intermediate part of conductor lead 15c, 16c Other end of conductor lead 21,22,23 , 24 Insulating film 27, 28 Conductor wiring

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiro Tanaka 1006 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-217296 (JP, A) JP-A-3-3 45399 (JP, A) JP-A-2-139784 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06K 19/077 G11C 5/00 B42D 15/10 521

Claims (1)

(57) [Claims] An end of a conductor lead connected to an electrode of a memory LSI chip, and an intermediate portion and the other end of the conductor lead connected to a common electrode of the memory LSI chip connected by an insulating film; A plurality of chips are stacked on the printed wiring board in a direction in which the arrangement of the electrodes is the same, and a portion between the middle portion and the other end portion of the conductor lead connected to the common electrode is partially overlapped with the printed wiring board. The memory LSI
A set in which the electrode surface of the chip is stacked in a direction facing the printed wiring board; and a set in which the electrode surface of the memory LSI chip is stacked in a direction not facing the printed wiring board. 3. The IC memory card according to claim 1, wherein the length between the middle part and the other end of the conductor lead is the same.