KR940006122B1 - Thin layer ic card - Google Patents

Abstract

No content.

Description

Thin film IC card

1 is a structural diagram of a conventional laminated IC card.

2 is a cross-sectional view of a conventional retractable IC card.

3 is an embodiment of an IC card according to the present invention, in which FIG. 3 (a) is a structural diagram of the IC card, and FIG. 3 (b) is a sectional view of the center sheet.

* Explanation of symbols for main parts of the drawings

1, 4, 6, 31: opening 2: upper exterior film

3: upper metal body 5: top sheet

7, 32: upper sheet 8, 22, 33: terminal

9: CPU chip 10: memory chip

11, 34: center sheet 12, 35: lower sheet

13 lower metal body 14 lower surface sheet

15: lower outer film 20, 30: IC module

21: Through hole 23: IC chip

24: institution 25: IC card

26: thin vinyl chloride sheet 27: sealing resin

28: bonding wire 41: metal sheet

42, 47: insulating layer 43: gate electrode

44 gate insulating film 45 semiconductor layer

46 contact layer 48 source and drain electrodes

49: protective layer 50: metal film for the terminal

51: contact groove

The present invention is applicable to credit cards, cash cards, public telephone cards, and the like, and in particular, it is possible to improve the resistance to warpage by using a flexible substrate while reducing the price by thinning the IC used in the IC card. It relates to the structure of a thin film IC card.

By inserting ICs such as CPU and memory into a plastic card of the same type as the magnetic card, the IC card can manage information with the built-in software, making it difficult to modify or counterfeit and verify user's legitimacy within the card. As it has a high level of safety, as it is not influenced by external magnetism, it has been in the spotlight as the informatization of society has progressed. In addition, the IC card has the advantage of larger memory capacity and higher versatility than the existing magnetic card. However, it is the biggest disadvantage of the IC card, and the built-in IC may be damaged if the card is bent. have. IC cards can be divided into two types, laminate type and insert type, depending on the manufacturing method. 1 is a structural diagram of a laminated IC card, which is suitable for mass production, and a thin film of an IC module 20 manufactured by TAB (Tape Automated Bonding) method, which is suitable for mass production, and which can be thinned. It's a way to work with. However, in the TAB method, a bump that serves to connect the IC chip and the lead wire formed on the tape, which is the substrate, must be formed, and because the expensive material is used, the manufacturing price becomes expensive. Also, the insertion type IC card (Japanese Laid-Open Patent Publication No. 58-138057) shown in FIG. 2 is sealed after connecting the IC chip 23 and the double-sided board (or lead frame) 24 with wirebonding 28. FIG. The IC module 30 formed by molding the resin 27 is fixed to the groove formed in the card substrate (thin vinyl chloride plate) 26 by using an adhesive. In this way, there is a disadvantage in that the thickness of the IC module 30 becomes thicker by wire bonding, and the groove for inserting the IC module 30 into the card substrate 26 must be precisely processed, as well as the IC module ( 30) and the reliability of the adhesion of the card substrate 26 should also be increased.

As is well known, laminated and retractable IC cards require a high level of process to modularize IC chips in common, which not only increases manufacturing costs but also hinders mass production, and the thickness of IC chips themselves (4 inch silicon wafer). Is about 0.5 mm) and the thickness of the substrate used in the IC module has a limitation in thinning. In addition, to prevent the IC chip from being damaged by external pressure, a reinforcing plate is laminated in the card body (JP-A-60-189587), or a gap is formed around the IC module (JP-A-63-120690). Measures are required. In addition, there is a problem in that a conductor must be separately installed in the card main body to protect the IC chip from noise such as static electricity.

The present invention has been made to solve the above problems, the purpose is to improve the resistance to bending of the IC card, to further reduce the thickness of the thin film card, and to simplify the manufacturing process to increase the productivity.

The configuration of one embodiment of the thin film IC card according to the present invention and its manufacturing method will be described next with reference to FIG. Referring to FIG. 3 (a), the thin film IC card according to the present invention includes an upper sheet 32, a center sheet 34, and a lower sheet 35, wherein the center sheet 34 includes a thin film transistor (thin). As a method of manufacturing a film transistor, a CPU and a memory are integrated, and a terminal unit for connection between the CPU and the memory is formed. The upper sheet 32 and the lower sheet 35 support and protect the center sheet 34 or integrated circuits formed therein, and also serve as an exterior material of the IC card. The upper sheet 32 and the lower sheet 35 are formed of a plastic such as vinyl chloride, which is generally used as a material of an IC card, and the upper sheet 32 has terminals of an integrated circuit formed on the center sheet 34. There is a hole to expose them to the outside.

3 (b) shows the configuration of the center sheet 34 according to the embodiment of the present invention.

As described above, in the center sheet 34, semiconductor integrated circuits are formed by a method of manufacturing a thin film transistor, which is described by M. Bohm et al in "Applied Physics A 45 (1988)". The transistors are mainly formed according to a well-known method of manufacturing a thin film transistor, but in the present invention, the transistors are formed in the center sheet 34 by a method in which the above method is applied to be suitable for the manufacture of an IC card. In other words, the substrate on which the integrated circuit of the IC card is formed requires the following conditions. The substrate positioned at the bottom of the center sheet 34 on which the integrated circuit formed of the thin film transistors is to be formed should be an insulator having electrical insulation and made of a material having a certain hardness to enable the integrated circuit manufacturing process. do. In addition, in order to thin the card, the thickness of the center sheet substrate should be sufficiently thin. In addition, in order to have resistance to warpage, the substrate is required to have a certain degree of flexibility.

In order to satisfy the above conditions, in the present invention, the insulating sheet 42 formed of a dielectric thin film such as a heat resistant polymer such as polyimide (po1yimide) or a silicon oxide film is formed on the stainless stick thin plate 41. It is used as a substrate of 34). In particular, since the polyimide can be coated in a liquid state, a smooth substrate can be formed without mirror polishing the lower metal plate 41.

An integrated circuit is formed on the substrate by the above-described thin film transistor manufacturing method. In the present invention, in manufacturing a thin film transistor, amorphous silicon is used as the semiconductor material which is physically or chemically stable and capable of a low temperature process of 400 ° C. or less, and which has excellent selectivity of a semiconductor substrate. In this case, in order to improve the characteristics of the thin film transistor, the amorphous silicon may be formed as a transistor after recrystallization by a laser or the like.

After the integrated circuit fabrication process is completed, a passivation layer 49 is coated on the semiconductor substrate with a dielectric thin film such as a silicon nitride film, and the like, and then connected to the terminals of the integrated circuit on the passivation layer 49. The contact groove 51 is formed.

Thereafter, a metal film 50 is coated on the protective layer 49 to connect between the terminals of the integrated circuit and the external terminal to form a pattern of the external terminal. In the above terminal pattern forming process, the metal film 50 coated on the circuit portion of the thin film transistor is left without being removed, because the metal film on the circuit portion of the thin film transistor is separated from the external electrical noise together with the metal thin plate 41. This is to protect the integrated circuit (that is, the thin film transistor formed on the center sheet 34) of the IC card.

As described above, according to the present invention, first, by forming the external terminal of the integrated circuit together on the center sheet 34, a complicated and difficult modularization process can be omitted, and the integrated circuit is manufactured by the thin film device manufacturing process. As a result, inexpensive substrates can be used compared to the single crystal silicon substrates used in the manufacture of integrated circuits in the related art, and large-area substrates can be manufactured. Second, the center sheet itself has a function to protect the integrated circuit in the card from external electrical noise, so that a separate noise prevention process is not required in manufacturing the IC card. Third, by using a flexible substrate, the resistance to bending can be enhanced and thus the stability of the IC card can be more firmly ensured. Fifth, by thinning the whole process, the card thickness can be greatly reduced, and thus the portability of the card can be improved. Finally, since the modularization process is not necessary and all the circuits are concentrated in one sheet, the cardization process can be simplified, thereby increasing the productivity.

Claims (4)

In the structure of the thin film IC card in which the integrated circuit is embedded; Insulating substrates 41 and 42 having electrical insulation and the integrated circuit are formed on the insulating substrate in a thin film transistor structure together with external terminals for connecting them, and the integrated circuit to protect the integrated circuit of the thin film transistor structure. A dielectric film 49 formed over the entire substrate on which the substrate is formed, and the external terminal is connected to the integrated circuit through a contact groove 51, and a metal film 50 formed on the dielectric thin film in the region where the integrated circuit is formed. A center sheet 34 comprising; An upper sheet 32 and a lower sheet 35 attached to upper and lower surfaces of the center sheet 34 to support and protect the integrated circuit formed on the center sheet 34 and used as an exterior material; The upper sheet 32 and the lower sheet 35 are formed of plastic, and the upper sheet 32 has a hole for exposing the terminals of the integrated circuit formed in the center sheet 34 to the outside. Thin film IC card characterized in that. The thin film IC card according to claim 1, wherein said insulating substrate comprises a metal thin plate (41) and an insulating film (42) coated on said metal thin plate (41). 3. The thin film IC card according to claim 2, wherein the metal thin plate (41) comprises stainless steel. 3. The thin film IC card according to claim 2, wherein said insulating film (42) comprises either a heat resistant polymer film or a dielectric film.

Images