A highly reliable non-contact lead frame

Abstract

This application belongs to the technical field of smart card packaging, and particularly relates to a new type of high-reliability non-contact lead frame. The non-contact lead frame includes a carrier tape, the carrier tape includes a chip bearing area and a plurality of chip wire bonding areas, the chip wire bonding areas are located around the chip bearing area, a number of densely distributed pits are arranged on the chip bearing area, and the area size of the chip bearing area where the pits are arranged is larger than the size of the chip bonded on the chip bearing area. On the opposite sides of the chip bearing area and the chip wire bonding area, a plurality of pairs of shrinkage openings are arranged at intervals, so that the distance between the inner edge of the chip bearing area and the outer edge of the chip wire bonding area becomes larger at the shrinkage openings. This application improves the tolerance of the carrier tape during stamping, ensures the surface flatness of the non-contact carrier tape, increases the chip bonding strength and the module peeling strength, makes the mechanical properties of the packaging module stronger, and the performance more stable and reliable.

Description

Technical Field

[0001] This application belongs to the technical field of smart card packaging, and particularly relates to a high-reliability non-contact lead frame and a production and processing method thereof. Background Art

[0002] With the continuous improvement of the integration level of integrated circuits and the increasingly perfect functions, the application scenarios of smart cards are becoming more and more diverse. With the continuous popularization of the Internet of Everything, users' demand for the security level of smart card use is constantly increasing, and non-contact modules are widely used due to their extremely high security.

[0003] With the continuous enrichment of the application scenarios of non-contact modules, users' requirements for the usage conditions of products are becoming more and more stringent. The existing packaging technology has been difficult to meet users' requirements for the mechanical properties of non-contact modules. Therefore, it is necessary to improve the existing packaging technology of non-contact modules and seek a breakthrough point for improving the mechanical properties of the modules.

[0004] Bonding strength and peel strength are the main indicators recognized in the industry for evaluating the packaging quality of non-contact modules. Non-contact carrier tape is an indispensable raw material for non-contact module packaging. The applicability of the carrier tape structure largely determines the bonding strength and peel strength of the packaged module. Therefore, in order to break the current situation where it is difficult to improve the packaging quality of existing non-contact modules, the design and transformation of non-contact carrier tape is a new breakthrough point for opening up a new situation in non-contact module packaging.

[0005] The packaging process of non-contact modules mainly includes: first, bonding the chip on the surface of the non-contact carrier tape through adhesive tape, then using bonding wires to connect the chip and the carrier tape to achieve circuit conduction, and finally injecting encapsulant to form a protective layer on the surface of the chip, thereby increasing the reliability of the non-contact module during use. As the chip carrier, the carrier tape plays an important role in the entire packaging process. There are the following three problems with the existing carrier tape during use:

[0006] (1) During the production and use of the carrier tape, it will undergo multiple repeated stamping operations, resulting in changes in the carrier tape density and uneven distribution, which causes the flatness of the carrier tape to decrease, resulting in quality problems such as wire punching, chromium printing, and overflow in the production of non-contact modules;

[0007] (2) The adhesive tape is coated on the chip-bearing area of the non-contact carrier tape. To ensure the bonding strength of the chip, a certain thickness of adhesive tape needs to be coated on the chip-bearing area. Due to the smooth and flat surface of the chip-bearing area, it is easy to have uneven glue coating during the glue coating process, resulting in problems such as insufficient back glue and voids on the chip, and a series of problems such as low bonding strength and low point pressure force value, resulting in poor packaging quality of non-contact modules;

[0008] (3) Under the existing materials and packaging technologies, the adhesion between the plastic encapsulant and the carrier tape is not strong, and it is difficult to improve the peel strength of the packaging module, which becomes a key factor restricting the further expansion of the usage scenarios of non-contact modules. Summary of the Invention

[0009] To solve at least one of the above technical problems, the present application provides a highly reliable non-contact lead frame. The non-contact lead frame includes a carrier tape, and the carrier tape includes a chip-bearing area and a plurality of chip wire-bonding areas. The chip wire-bonding areas are located around the chip-bearing area. A number of densely distributed pits are arranged on the chip-bearing area, and the area size of the chip-bearing area where the pits are arranged is larger than the size of the chip bonded on the chip-bearing area. On both opposite sides of the chip-bearing area and the chip wire-bonding areas, a plurality of pairs of shrinkage openings are arranged at intervals, so that the distance between the inner edge of the chip-bearing area and the outer edge of the chip wire-bonding area becomes larger at the shrinkage openings.

[0010] Preferably, the pits are arranged as depressions with a cubic structure, and the side length of the cubic structure is set to be 0.018 - 0.022 mm.

[0011] Preferably, the pits are arranged as depressions with a hemispherical structure, and the radius of the hemispherical structure is 0.018 - 0.022 mm.

[0012] Preferably, the pits are arranged as trapezoidal structures with a narrow opening and a wide bottom.

[0013] Preferably, the chip wire-bonding area includes an upper part and a lower part. The inner edge of the upper part of the chip wire-bonding area is a semi-circular arc line, and the semi-circular arc line faces at least a part of the upper horizontal side of the chip-bearing area and the vertical sides on both sides of the upper horizontal side. Correspondingly, the inner edge of the lower part of the chip wire-bonding area is a semi-circular arc line, and the semi-circular arc line faces at least a part of the lower horizontal side of the chip-bearing area and the vertical sides on both sides of the lower horizontal side. Each of the upper part and the lower part of the chip-bearing area includes three shrinkage openings, one of which is located at the center of the upper or lower horizontal side of the chip-bearing area, and the other two are located at both ends of the upper or lower horizontal side.

[0014] Preferably, the shrinkage openings are arc-shaped shrinkage openings.

[0015] Preferably, the radius R of the arc-shaped shrinkage opening is set as:

[0016] R = L / [(E + G)v / 2];

[0017] Wherein, L is the distance between two adjacent shrinkage openings on the upper or lower horizontal side of the chip carrying area, E is the elastic modulus of the carrier tape material, G is the shear modulus of the carrier tape material, and v is the Poisson's ratio.

[0018] Preferably, after the chip is encapsulated on the chip carrying area, the non-bonding area of the chip carrying area that exceeds the chip size is filled with encapsulant.

[0019] Preferably, a stepped structure is provided on the surfaces of the chip carrying area and the chip wire bonding area.

[0020] This application improves the tolerance of the carrier tape during stamping, ensures the surface flatness of the non-contact carrier tape, increases the chip bonding strength and the module peeling strength, makes the mechanical properties of the encapsulated module stronger, the performance more stable and reliable, suitable for large-scale mass production, and the application scenarios of the encapsulated module are more diverse. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the ejector pin in the high-reliability non-contact lead frame of this application.

[0022] Wherein, 1-chip carrying area, 2-chip wire bonding area, 3-pit, 4-shrinkage opening. Detailed Embodiments

[0023] To make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the drawings in the embodiments of this application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are some but not all of the embodiments of this application. The embodiments described below with reference to the drawings are exemplary and are intended to explain this application and should not be construed as limiting this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the drawings.

[0024] In the description of this application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application.

[0025] The following combines the attachedFigure 1 A further detailed description of the high-reliability non-contact lead frame of the present application is provided.

[0026] The present application provides a novel high-reliability non-contact lead frame. The non-contact lead frame includes a carrier tape, and the carrier tape includes a chip-bearing area 1 and a plurality of chip wire-bonding areas 2. The chip wire-bonding areas 2 are located around the chip-bearing area 1. A number of densely distributed pits 3 are arranged on the chip-bearing area 1, and the area size of the area where the pits 3 are arranged on the chip-bearing area 1 is larger than the size of the chip bonded on the chip-bearing area 1. On the opposite sides of the chip-bearing area 1 and the chip wire-bonding area 2, a plurality of pairs of shrinkage openings 4 are arranged at intervals, so that the distance between the inner edge of the chip-bearing area 1 and the outer edge of the chip wire-bonding area 2 becomes larger at the shrinkage openings.

[0027] In the present application, by adding shrinkage openings at multiple positions in the non-contact chip-bearing area and the wire-bonding area, when the carrier tape is affected by strong external forces, the ductility of the carrier tape is increased, the density of each part of the carrier tape is balanced to a certain extent, and the flatness of the surface of the carrier tape is effectively improved.

[0028] By improving the surface of the traditional non-contact carrier tape in the present application, a dimpling structure is added. When the die bonding adhesive is coated on the surface of the chip-bearing area, in addition to planar coating, it will also penetrate into the dimpling of the carrier tape, thereby increasing the bonding strength between the chip and the carrier tape.

[0029] In some alternative embodiments, the pits are set as depressions with a cubic structure, and the side length of the cubic structure is set to 0.018 - 0.022 mm.

[0030] In some alternative embodiments, the pits are set as depressions with a hemispherical structure, and the radius of the hemispherical structure is 0.018 - 0.022 mm.

[0031] In a specific embodiment, the surface of the traditional non-contact carrier tape is improved in the present application, and a dimpling structure with a length, width, and height of 0.02 mm is added.

[0032] In some alternative embodiments, the pits are set as trapezoidal structures with a narrow opening and a wide bottom. The adhesive material can be cured inside the pits through the trapezoidal structure with a narrow opening and a wide bottom, thereby enhancing the connection strength between the adhesive material and the carrier tape, and further enhancing the connection strength between the chip and the carrier tape. In alternative embodiments, the pits can also be set as wavy structures with multiple corrugated edges, which can also enhance the connection strength between the chip and the carrier tape.

[0033] In some alternative embodiments, the chip wire bonding area 2 includes an upper half and a lower half. The inner edge of the upper half of the chip wire bonding area 2 is a semi-circular line, and the semi-circular line faces at least a part of the upper horizontal edge of the chip carrying area 1 and the vertical edges on both sides of the upper horizontal edge. Correspondingly, the inner edge of the lower half of the chip wire bonding area 2 is a semi-circular line, and the semi-circular line faces at least a part of the lower horizontal edge of the chip carrying area 1 and the vertical edges on both sides of the lower horizontal edge. Each of the upper half and the lower half of the chip carrying area 1 includes three shrinkage openings 4, one of which is located at the center of the upper horizontal edge or the lower horizontal edge of the chip carrying area 1, and the other two are located at both ends of the upper horizontal edge or the lower horizontal edge.

[0034] In some alternative embodiments, the shrinkage opening is an arc-shaped shrinkage opening.

[0035] In some alternative embodiments, the radius R of the arc-shaped shrinkage opening is set as:

[0036] R = L / [(E + G)v / 2];

[0037] Wherein, L is the distance between two adjacent shrinkage openings on the upper horizontal edge or the lower horizontal edge of the chip carrying area 1, E is the elastic modulus of the carrier tape material, G is the shear modulus of the carrier tape material, and v is the Poisson's ratio.

[0038] For example, for rolled aluminum material, the elastic modulus is 70, the shear modulus is 30, the Poisson's ratio is 0.3. When the distance between two adjacent shrinkage openings on the upper horizontal edge of the chip carrying area is 15 cm, the shrinkage opening R is calculated to be 1 cm. The result of this calculation takes into account the elastic modulus and shear modulus of the material, as well as the size and distance of the shrinkage opening, ensuring the full release of stress after the material is compressed, preventing stress concentration, and increasing the ductility of the carrier tape.

[0039] In some alternative embodiments, after the chip is encapsulated on the chip carrying area 1, the non-bonding area of the chip carrying area 1 that exceeds the chip size is filled with encapsulant.

[0040] In this embodiment, since the area of the Dimpling structure of the newly designed carrier tape is larger than the chip area, the encapsulant will be filled in the Dimpling area except the chip area during encapsulation, thus effectively increasing the peel strength of the module.

[0041] In some alternative embodiments, a stepped structure is provided on the surfaces of the chip carrying area 1 and the chip wire bonding area 2.

[0042] In this embodiment, the chip carrier area and wire bonding area of the carrier tape are designed with a stepped structure. When the encapsulant is injected, it will enter the stepped structure, increasing the bonding force between the encapsulant and the carrier tape and improving the mechanical properties of the packaging module.

[0043] This application improves the traditional non-contact carrier tape structure. The Dimpling structure and the punching structure improve the tolerance of the carrier tape during stamping, ensure the surface flatness of the non-contact carrier tape, increase the chip bonding strength and the module peeling strength, making the mechanical properties of the packaging module stronger, the performance more stable and reliable, suitable for large-scale mass production, and the application scenarios of the packaging module are more diverse.

[0044] As described above, the above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A highly reliable non-contact lead frame, the non-contact lead frame comprising a carrier tape, the carrier tape including a chip carrying area (1) and a plurality of chip wire bonding areas (2), the chip wire bonding areas (2) being located around the chip carrying area (1), characterized in that, A number of densely distributed pits (3) are arranged on the chip bearing area (1), and the area size of the area where the pits (3) are arranged on the chip bearing area (1) is larger than the size of the chip bonded on the chip bearing area (1). On the opposite sides of the chip bearing area (1) and the chip wire bonding area (2), a plurality of pairs of shrinkage openings (4) are arranged at intervals, so that the distance between the inner edge of the chip bearing area (1) and the outer edge of the chip wire bonding area (2) becomes larger at the shrinkage openings; Among them, the chip wire bonding area (2) includes an upper part and a lower part. The inner edge of the upper part of the chip wire bonding area (2) is a semi-circular arc line, and the semi-circular arc line faces at least a part of the upper horizontal edge of the chip bearing area (1) and the vertical edges on both sides of the upper horizontal edge. Correspondingly, the inner edge of the lower part of the chip wire bonding area (2) is a semi-circular arc line, and the semi-circular arc line faces at least a part of the lower horizontal edge of the chip bearing area (1) and the vertical edges on both sides of the lower horizontal edge. Each of the upper part and the lower part of the chip bearing area (1) includes three shrinkage openings (4), one of the shrinkage openings is located at the center of the upper horizontal edge or the lower horizontal edge of the chip bearing area (1), and the other two shrinkage openings are located at both ends of the upper horizontal edge or the lower horizontal edge.

2. The highly reliable non-contact lead frame according to claim 1, wherein The pits are arranged as cubic-shaped depressions, and the side length of the cubic-shaped structure is set to 0.018 - 0.022 mm.

3. The highly reliable non-contact lead frame according to claim 1, characterized in that, The pits are arranged as hemispherical-shaped depressions, and the radius of the hemispherical-shaped structure is 0.018 - 0.022 mm.

4. The highly reliable non-contact lead frame according to claim 1, wherein The pits are arranged as trapezoidal structures with a narrow opening and a wide bottom.

5. The highly reliable non-contact lead frame according to claim 1, characterized in that The shrinkage openings are arc-shaped shrinkage openings.

6. The highly reliable non-contact lead frame according to claim 5, characterized in that, The radius R of the arc-shaped shrinkage opening is set to: R = L / [(E + G)v / 2]; where L is the distance between two adjacent shrinkage openings on the upper horizontal edge or the lower horizontal edge of the chip bearing area (1), E is the elastic modulus of the carrier tape material, G is the shear modulus of the carrier tape material, and v is the Poisson's ratio.

7. The highly reliable non-contact lead frame according to claim 1, wherein After the chip is encapsulated on the chip bearing area (1), the non-bonding area of the chip bearing area (1) that exceeds the chip size is filled with encapsulant.

8. The highly reliable non-contact lead frame according to claim 1, wherein The surfaces of the chip bearing area (1) and the chip wire bonding area (2) are provided with a stepped structure.

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