Ultrathin intelligent card packaging structure of large golden finger
By using a stepped stacking structure of large gold fingers and non-functional chips, the problems of low packaging rate and chip deformation and cracking in smart card products are solved, achieving ultra-thin smart card packaging with high reliability and high yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 中电智能卡有限责任公司
- Filing Date
- 2025-04-24
- Publication Date
- 2026-05-15
AI Technical Summary
In existing smart card product packaging, the large size of the memory chip leads to a low packaging rate, and when there are many chip layers, they are prone to deformation or cracking, which affects product reliability and yield.
The design employs a large gold finger and a non-functional chip. Through a stepped stacking structure of substrate, non-functional chip and functional chip, molding compound is used to fill the gaps, isolate stress, and prevent functional chip deformation or cracking.
It improves packaging yield, prevents functional chip failure, enhances product aesthetics and reliability, and reduces packaging difficulty and cost.
Smart Images
Figure CN224250170U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of smart card manufacturing technology, and specifically relates to an ultra-thin smart card packaging structure with a large gold finger. Background Technology
[0002] With the development of portable electronic products, there are requirements for the packaging of smart card products to be lightweight, thin, small, high-storage, and highly reliable. The packaging of ultra-thin smart card products cannot be separated from the stacking or layering of chips, that is, the smart card chips are stacked in a vertical or stepped manner to achieve multi-chip packaging, thereby achieving the purpose of high storage and small size.
[0003] However, in the current packaging of smart card products, the memory chips used are often very large. This results in a very low yield rate, even though smart card chips can be packaged using either vertical stacking or stepped stacking. Often, due to the excessive number of chip layers and the need to reduce chip thickness while ensuring the ultra-thinness of the smart card product, the rigidity of the smart card chip is reduced. This leads to deformation or even cracking during the surface mount process, resulting in product failure and a low packaging rate. Utility Model Content
[0004] The purpose of this application is to provide an ultra-thin smart card packaging structure with a large gold finger to solve or mitigate at least one of the problems in the prior art.
[0005] The technical solution of this application is: an ultra-thin smart card packaging structure with a large gold finger, comprising:
[0006] A substrate having a bottom surface and a top surface opposite each other, the bottom surface having gold fingers and the top surface having surface-mount devices, non-functional chips and / or functional chips;
[0007] A non-functional chip, wherein the non-functional chip is disposed on the top surface of the substrate and in the area adapted to the gold finger;
[0008] A functional chip, comprising at least two layers and stacked in a stepped manner on the top surface of a non-functional chip, wherein the functional chip is bonded to a substrate via metal wires;
[0009] A molding compound, which is filled between the substrate, the non-functional chip and / or the functional chip, for encapsulating the substrate, the non-functional chip and the functional chip;
[0010] The gold fingers are multiple, and the area of each gold finger is not less than 10% of the area of the ultra-thin smart card. The total area of the multiple gold fingers is not less than 60% of the area of the ultra-thin smart card, and the area of the non-functional chip corresponding to each gold finger is not greater than the area of the gold finger at the corresponding position on the substrate.
[0011] Preferably, the non-functional chip is not electrically connected to the substrate and / or the functional chip.
[0012] Preferably, the gold finger is made of copper, copper alloy, or gold.
[0013] Preferably, the area of at least one functional chip disposed on the non-functional chip in the functional chip is not less than 70% of the area of the ultra-thin smart card.
[0014] Preferably, the thickness of the functional chip closer to the non-functional chip is greater than the thickness of the other functional chips.
[0015] Preferably, the thickness of the non-functional chip is not greater than the thickness of the functional chip.
[0016] Preferably, the area of the non-functional chip is not less than 45% of the area of the gold finger.
[0017] The ultra-thin smart card packaging structure with large gold fingers provided in this application can alleviate the stress between the gold fingers of the substrate and the functional chip in ultra-thin smart card products, prevent the functional chip from deforming or even cracking, which would lead to the loss of function of the functional chip, thereby improving the product packaging yield. Attached Figure Description
[0018] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.
[0019] Figure 1 This is a schematic diagram of the ultra-thin smart card packaging structure of the large gold finger in this application.
[0020] Figure 2 The diagram shows the non-functional chip distribution and perspective view of the ultra-thin smart card packaging structure with gold fingers, which is the basis of this application.
[0021] Figure 3 This is a schematic diagram of the wire bonding of the ultra-thin smart card packaging structure for the large gold finger of this application. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.
[0023] like Figure 1 As shown, the ultra-thin smart card packaging structure of the large gold finger provided in this application includes: a substrate 1, several layers of functional chips 2, non-functional chips 3, and molding compound 4.
[0024] The substrate 1 has a multi-layer structure. Its bottom surface has several large gold fingers 11, and its top surface has several lead pads 13. A non-functional chip 3 is disposed on the top surface of the substrate 1, corresponding to the area of the gold fingers 11. Surface mount devices 12 are also mounted on the top surface of the substrate 1. Several layers of functional chips 2 are stacked on top of the non-functional chips 3, and the gaps between the substrate 1, the non-functional chips 3, and the functional chips 2 are filled with molding compound 4.
[0025] In this application, a plurality of gold fingers 11 are provided on the bottom surface of the substrate 1. Each gold finger 11 has a relatively large area, and the area of a single gold finger 11 can account for more than 10% of the area of the ultra-thin smart card, and the total area of the plurality of gold fingers 11 accounts for more than 60% of the area of the ultra-thin smart card. Figure 2 The diagram shows a perspective view of a substrate 1 with a non-functional chip 3 disposed on it, according to an embodiment of this application. The bottom surface of the substrate 1 has six large-area gold fingers 11, arranged in two rows of three. Several lead pads 13 (i.e., the rectangles and squares filled in black in the diagram) are formed at the edge of the top surface of the substrate 1. Several surface mount devices 12 (i.e., C1 to C7, etc., located on the lower and right sides of the drawing) are also attached to the top surface of the substrate 1. The non-functional chip 3 is disposed on the top surface of the substrate 1, corresponding to the area of the gold fingers 11. The area of each non-functional chip 11 is not less than 45% of the area of the corresponding gold finger 11, thereby effectively achieving stress isolation between the gold fingers 11 and the functional chip 2. The non-functional chip 3 is only disposed on the substrate 1 and does not have any electrical connection with the substrate 1 or the functional chip 2.
[0026] The Gold Finger 11 is a conductive contact used for electrical connection in ultra-thin smart cards. Its material is usually copper, copper alloy or gold, which have good conductivity, thus providing conductivity and mechanical strength.
[0027] In this application, the functional chip 2 has at least two layers and is arranged in a stepped stacking manner above the non-functional chip 3. Figure 1 and Figure 3As shown, the functional chip 2 in this embodiment of the application includes a first functional chip 21, a second functional chip 22, a third functional chip 23, a fourth functional chip 24, a fifth functional chip 25, and a sixth functional chip 26. The first functional chip 21, the second functional chip 22, the third functional chip 23, and the fourth functional chip 24 have large areas, each occupying more than 70% of the entire ultra-thin smart card area. The areas of the first functional chip 21, the second functional chip 22, the third functional chip 23, and the fourth functional chip 24 can be set to be the same or different. The first functional chip 21 to the fourth functional chip 24 are arranged in a stepped stacked package on the upper side of the non-functional chip 3, thereby allowing the upper functional chip 2 to be offset from the lower functional chip 2 by a certain position. This provides sufficient area and space on the surface of the lower functional chip 2 to perform wire bonding with the lead pads 13 on the substrate 1. Wire bonding connects the functional chip 2 to the external substrate 1 through metal wires to achieve electrical signal transmission. For example, the metal wires used in wire bonding include gold wire (Au) and copper wire (Cu). When gold wire (Au) is used for wire bonding, good conductivity and oxidation resistance can be achieved, and its diameter can usually be set to 15μm-50μm. When copper wire (Cu) is used for wire bonding, higher cost performance can be achieved, and its diameter can usually be set to 20μm-75μm.
[0028] In a preferred embodiment of this application, the thickness of the functional chip 2 located at the bottom layer (i.e., the side closer to the non-functional chip 3) is generally greater than the thickness of the functional chip 2 located at the top layer, thereby providing better support for the functional chip 2 located at the bottom layer. For example, in this embodiment of this application, the thickness of the first functional chip 21 located at the bottom layer is 80μm to 140μm, and the thickness of the second functional chip 22 to the fourth functional chip 24 located at the top layer is 40μm to 80μm. It should be noted that although the thickness range of the second functional chip 22 to the fourth functional chip 24 overlaps with the thickness range of the first functional chip 21, when the second functional chip 22 to the fourth functional chip 24 are set with thickness values within their thickness range, the first functional chip 21 is usually also selected with a thickness value greater than that set by the second functional chip 22 to the fourth functional chip 24 within its thickness range.
[0029] like Figure 3As shown, the areas of the fifth functional chip 25 and the sixth functional chip 26 are much smaller than those of the first functional chips 21 to the fourth functional chips 24, and their sizes are similar to those of the gold finger 11. To realize the chip's function, the fifth functional chip 25 and the sixth functional chip 26 are respectively attached to the lower left and lower right corners of the top-layer fourth functional chip 24, and the two functional chips are wire-bonded to their surrounding lead pads 13. In some embodiments of this application, the fifth functional chip 25 and the sixth functional chip 26 have the same thickness as the larger, non-bottom-layer functional chips, that is, the thickness of the fifth functional chip 25 and the sixth functional chip 26 is 40μm to 80μm.
[0030] The thickness of the non-functional chip 3 in this application usually needs to be determined based on the thickness of the molding die, the total thickness of the internal chip, and the height of the wire bonding of the molding product. It should not be too thick or too thin to avoid problems such as failure to provide isolation stress or causing the product to be too thick. Therefore, in the preferred embodiment of this application, the thickness of the non-functional chip 3 at the corresponding position on the back of the gold finger of the substrate 1 can be set to 40μm to 70μm.
[0031] Before mounting the functional chip 2 of the ultra-thin smart card in this application, non-functional chips 3 are first mounted at corresponding positions of each gold finger 11 on the substrate 1. The position of each non-functional chip 3 is set according to the position of the gold finger 11, and the area of the non-functional chip 3 is smaller than the area of the corresponding gold finger 11 but not less than 45% of the area of the corresponding gold finger. After encapsulation with molding compound 4, the molding compound 4 particles can enter the gaps between the non-functional chip 3 and the substrate 1, between the non-functional chip 3 and the functional chip 2, and / or between adjacent non-functional chips 3. This relieves the stress between the gold fingers 11, ink, and functional chip 2 of the substrate 1 in the ultra-thin smart card product, prevents the functional chip 2 from deforming or even cracking, which would lead to the loss of function of the functional chip 2, thereby improving the product packaging yield.
[0032] The packaging process for the ultra-thin smart card with the large gold finger in this application is as follows:
[0033] S10, a surface mount device 12 is mounted at approximately the edge of the upper side surface of the substrate 1, for example... Figure 2 The black rectangular device shown;
[0034] S20, on the upper side of the mounting surface corresponding to each large gold finger on the substrate 1, non-functional chip 3 is mounted. After the non-functional chip 3 is mounted, multi-layer functional chip 2 is mounted. After the mounting is completed, it is cured.
[0035] S30, the functional chip 3 is wire bonded to the lead pad 13 on the substrate 1 using gold or copper wires to achieve electrical connection between the functional chip 3 and the substrate 1.
[0036] S40, after the wire bonding is completed, the substrate 1 is encapsulated using molding compound 4, and then post-curing is performed after encapsulation;
[0037] After S50 curing is completed, the entire substrate is divided into individual ultra-thin smart cards.
[0038] In the ultra-thin smart card packaging structure with large gold fingers provided in this application, since the gold fingers 11 on the substrate 1 are made of copper, copper alloy, or gold, which has high ductility, under the high temperature of the molding equipment, the stress of the gold fingers 11 is easily diffused to the surface of the ultra-thin smart card through the functional chip 2, resulting in the imprint of the gold fingers on the surface of the molded ultra-thin smart card. By adding non-functional chips 3, the stress can be effectively isolated, improving the product appearance and enhancing its aesthetics. It should be noted that the shape and size of the non-functional chip 3 in this application can be set according to the shape and size of the gold fingers 11, making it highly adaptable. There is no need to limit the thickness of the functional chip 2 or use special adhesive films to prevent the functional chip 2 from failing, reducing the packaging process difficulty. It is suitable for ultra-thin thicknesses of functional chips that require high-cost and difficult thinning and dicing processes or special adhesive films.
[0039] Through testing, it was verified that the injection-molded smart card products no longer exhibited the problem of cracking in the underlying and upper-layer functional chips, and the yield rate was improved by about 70%, demonstrating good practicality and beneficial effects.
[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A thin smart card packaging structure with a large gold finger, characterized in that, include: A substrate having a bottom surface and a top surface opposite each other, the bottom surface having gold fingers and the top surface having surface-mount devices, non-functional chips and / or functional chips; A non-functional chip, wherein the non-functional chip is disposed on the top surface of the substrate and in the area adapted to the gold finger; A functional chip, comprising at least two layers and stacked in a stepped manner on the top surface of a non-functional chip, wherein the functional chip is bonded to a substrate via metal wires; A molding compound, which is filled between the substrate, the non-functional chip and / or the functional chip, for encapsulating the substrate, the non-functional chip and the functional chip; The gold fingers are multiple, and the area of each gold finger is not less than 10% of the area of the ultra-thin smart card. The total area of the multiple gold fingers is not less than 60% of the area of the ultra-thin smart card, and the area of the non-functional chip corresponding to each gold finger is not greater than the area of the gold finger at the corresponding position on the substrate.
2. The ultra-thin smart card packaging structure with a large gold finger as described in claim 1, characterized in that, The non-functional chip is not electrically connected to the substrate and / or the functional chip.
3. The ultra-thin smart card packaging structure with a large gold finger as described in claim 1, characterized in that, The gold fingers are made of copper, copper alloys, or gold.
4. The ultra-thin smart card packaging structure with a large gold finger as described in claim 1, characterized in that, The area of at least one functional chip disposed on the non-functional chip in the functional chip is not less than 70% of the area of the ultra-thin smart card.
5. The ultra-thin smart card packaging structure with a large gold finger as described in claim 4, characterized in that, The thickness of the functional chip closer to the non-functional chip is greater than the thickness of the other functional chips.
6. The ultra-thin smart card packaging structure with a large gold finger as described in claim 4 or 5, characterized in that, The thickness of the non-functional chip is 40μm to 70μm.
7. The ultra-thin smart card packaging structure with a large gold finger as described in claim 6, characterized in that, The area of the non-functional chip is not less than 45% of the area of the gold finger.