Multi-turn high pin QFN product frame structure and packaging method

Abstract

The application provides a multi-circle high-pin QFN product frame structure, which can effectively and reliably package the multi-circle QFN product. The structure comprises a frame base island, a first circle of product pins, a second circle of product pins, and a third circle of product pins. The frame base island comprises a base island body, a base island edge ground ring, and a base island support web. The outer periphery of the frame base island is provided with the base island edge ground ring. The four corners of the base island edge ground ring are respectively provided with obliquely arranged flow guide strips. The outer ends of adjacent flow guide strips are connected by a first support entity web. The first support entity web is inwardly provided with a first circle of product pins and a second circle of product pins arranged at intervals. At least one outer convex base island support web is arranged on each side of the base island edge ground ring. The outer side of each side of the base island edge ground ring is respectively arranged with a parallel second support entity web, and the four second support entity webs are arranged in a surrounding manner.

Description

Technical Field

[0001] This invention relates to the technical field of QFN packaging, specifically to a multi-turn, high-pin, leadless QFN product frame structure. Background Technology

[0002] The semiconductor industry is developing rapidly, and the requirements for product performance are constantly increasing. However, different product application scenarios lead to increasing limitations on product size and performance requirements. Conventional single-turn or double-turn leadless products cannot be used in the market due to their large area and small number of pins. By integrating the internal lead frame design, the number of pins can be increased by 100% or more without changing the product area, thereby enabling the transmission of more signals. This allows the product to quickly transmit signals at the application end, stabilize product performance, and meet customer standards. It has excellent physical characteristics such as high temperature resistance, high voltage resistance, high frequency, and high power, bringing significant system advantages to industrial applications in terms of improved energy efficiency, system miniaturization, and improved voltage withstand, and has a very broad application prospect.

[0003] With the maturation of mass production technology, large-size, high-pin-count QFN products will become the mainstream semiconductor products in the future, applied in consumer electronics, data centers, 5G base stations, new energy vehicles, and many other fields. In semiconductors, high-pin-count, leadless QFN semiconductor devices are crucial for base station and power distribution and management. The design of the high-pin-count, leadless QFN product framework structure directly determines the corresponding semiconductor packaging structure. Therefore, there is an urgent need to develop a high-pin-count, leadless QFN product framework structure that enables efficient and reliable packaging of multi-turn QFN products. This will result in QFN products with advantages such as high conduction signal density, high output power density, good switching recovery characteristics, high heat dissipation efficiency, and excellent high-temperature operating characteristics. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a multi-turn high-pin leadless QFN product framework structure, which enables multi-turn QFN products to undergo effective and reliable packaging operations.

[0005] A multi-turn, high-pin, leadless QFN product frame structure, characterized in that it includes: The frame base island includes the base island body, the base island edge ground wire ring, and the base island support reinforcement; First ring of product pins; Second ring of product pins; And the third ring of product pins; The outer periphery of the frame base island is provided with a base island edge grounding ring. At the four corners of the base island edge grounding ring, obliquely arranged guide strips are respectively provided. The outer ends of adjacent guide strips are connected by a first supporting entity connecting rib. The first supporting entity connecting rib is provided with a first ring of product pins and a second ring of product pins arranged at intervals. At least one outwardly protruding base island supporting connecting rib is arranged on each side of the base island edge grounding ring. Parallel second supporting entity connecting ribs are arranged on the outer side of each side of the base island edge grounding ring. The four second supporting entity connecting ribs enclose and form a rectangular arrangement. Each second supporting entity connecting rib is arranged with a third ring of product pins protruding inward or outward.

[0006] Its further features are: It also includes a fourth ring of product pins, with a third ring of product pins arranged outwards on each of the second support body connecting ribs, and a fourth ring of product pins arranged inwards on each of the second support body connecting ribs. A base island support rib protrudes outward from the center of the length direction of each side of the base island edge ground wire ring. The outer end of the base island support rib is fixed to the center of the length direction of the second support entity rib at the corresponding position. The position of the base island support rib does not conflict with the position of the fourth ring of product pins. The back edge of the frame base island is designed with anti-overflow steps, and rectangular through holes are set at intervals on the anti-overflow steps. The outer periphery of the rectangular through holes is the ground wire ring of the base island edge. The position of the first ring of product pins corresponding to the first supporting entity connecting rib protrudes outward from the position of the second ring of product pins, and the third ring of product pins and the fourth ring of product pins are respectively provided on both sides of the second supporting entity connecting rib; The front sides of the first ring of product pins and the second ring of product pins are respectively provided with front half-etched structures, and the back sides of the front ends of the first ring of product pins and the second ring of product pins are respectively provided with back half-etched structures.

[0007] A packaging method for a multi-turn high-pin leadless QFN product frame is characterized by the following steps: First, the chip assembly is pre-fabricated and diced. Then, the chip is placed on the base island body to complete the die mounting. Next, the chip and the corresponding product pins of each turn are bonded together using bonding wires. Then, an adhesive film is applied to the back of the frame, followed by molding and curing. After molding, the frame is tinned and then printed. A first cut is made along the first cutting path to remove the connecting ribs of the second support entity, separating the product pins of the third and fourth turns, forming independent signals for each pin. Finally, a second cut is made to remove the connecting ribs of the first support entity, separating the product pins of the first and second turns.

[0008] By adopting this invention, the product area remains unchanged, but the number of pins is increased by changing the pin arrangement, enabling the transmission of more signals. This allows the product to quickly transmit signals at the application end, stabilize product performance, and meet customer usage standards. It possesses excellent physical characteristics such as high temperature resistance, high voltage resistance, high frequency, and high power, bringing significant system advantages to industrial applications in terms of improved energy efficiency, system miniaturization, and increased voltage resistance. Its application prospects are very broad. Furthermore, with the maturity of mass production technology, large-size, high-pin-area, multi-turn QFN products will become the mainstream semiconductor product in the future, applied in consumer electronics, data centers, 5G base stations, new energy vehicles, and many other fields. The improved performance of multi-turn, high-pin-area, leadless QFN semiconductor devices is the driving force behind the improvement of power system performance in terms of power density, power efficiency, operating frequency, and reliability. Moreover, the inherent characteristics of the multi-turn, high-pin-area, leadless QFN product framework structure determine that multi-turn, high-pin-area, leadless QFN devices have advantages such as high conduction signal density, high output power density, good switching recovery characteristics, high heat dissipation power efficiency, and excellent high-temperature operating characteristics. The multi-turn high-pin leadless QFN product frame structure enables efficient and reliable packaging of multi-turn QFN products. Attached Figure Description

[0009] Figure 1 This is a top view of the multi-turn high-pin leadless QFN product frame structure of the present invention; Figure 2 This is a process flow diagram of the packaging method of the present invention; Figure 3 This is a bottom view of the packaging structure of the present invention; The names corresponding to the serial numbers in the diagram are as follows: First ring of product pins 1, second ring of product pins 2, third ring of product pins 3, fourth ring of product pins 4, front half-etched structure 5, back half-etched structure 6, back edge half-etched of base island 7, base island edge ground ring 8, base island support rib 9, second support solid rib 10, silver plating layer on the front of base island body 11, silver plating layer on product pins 12, base island body 13, chip 14, die adhesive 15, molding compound 16, bonding wire 17, first dicing path 18, guide strip 19, first support solid rib 20, rectangular through hole 21 Detailed Implementation

[0010] The multi-turn, high-pin, leadless QFN product frame structure is shown in [reference]. Figure 1 It includes: a frame base island, a first ring of product pins 1, a second ring of product pins 2, and a third ring of product pins 3; The frame base island includes the base island body 13, the base island edge ground wire ring 8, and the base island support connecting ribs 9; The outer periphery of the base island is provided with a base island edge grounding ring 8. At the four corners of the base island edge grounding ring 8, there are obliquely arranged guide strips 19. The outer ends of adjacent guide strips 19 are connected by a first supporting entity connecting rib 20. The first supporting entity connecting rib 20 is provided with a first ring of product pins 1 and a second ring of product pins 2 arranged at intervals. At least one outwardly protruding base island supporting connecting rib 9 is arranged on each side of the base island edge grounding ring 8. Parallel second supporting entity connecting ribs 10 are arranged on the outer side of each side of the base island edge grounding ring 8. The four second supporting entity connecting ribs 10 enclose and form a rectangular arrangement. Each second supporting entity connecting rib 10 is arranged with a third ring of product pins 3 protruding inward or outward.

[0011] For specific embodiments, see Figure 1 It also includes a fourth ring of product pins 4, and each second support solid connecting rib 10 has a third ring of product pins 3 arranged outwardly, and each second support solid connecting rib 10 has a fourth ring of product pins 4 arranged inwardly. A base island support rib 9 protrudes outward from the center of the length direction of each side of the base island edge ground wire ring 8. The outer end of the base island support rib 9 is fixed to the center of the length direction of the second support entity rib 10 at the corresponding position. The position of the base island support rib 9 does not conflict with the position of the fourth ring product pin 4. In a specific embodiment, an anti-overflow step is designed on the back edge of the frame base island, and a spaced rectangular through hole 21 is set on the anti-overflow step. The outer periphery of the rectangular through hole 21 is the base island edge ground wire ring 8. The position of the first ring of product pins 1 corresponding to the same first supporting solid rib 20 protrudes outward from the position of the second ring of product pins 2. The width of the same second supporting solid rib 10 is 0.65~1.00mm. Four second supporting solid ribs 10 form a closed solid rib around the base island body 13. The third ring of product pins 3 and the fourth ring of product pins 4 are respectively provided on both sides of each second supporting solid rib 10. The front sides of the first ring of product pins 1 and the second ring of product pins 2 are respectively provided with a 5-15um front half-etched structure 5, and the front back sides of the first ring of product pins 1 and the second ring of product pins 2 are respectively provided with a 15-50um back half-etched structure 6.

[0012] During the fabrication of the frame structure, its shape is first etched out using an etching method, and then silver is selectively electroplated onto the pins and base island to form a silver plating layer 11 on the front of the base island body and a silver plating layer 12 on the product pins.

[0013] For the packaging method of multi-turn high-pin no-lead QFN product frames, see [link to packaging method]. Figures 1-3The process involves prefabricating a multi-ring high-pin, leadless QFN product frame structure 100, then thinning the chipset and dicing it. The chip 14 is then placed on the base island body 13 and mounted using adhesive 15. The chip 14 is then bonded to the first ring of product pins 1, the second ring of product pins 2, the third ring of product pins 3, and the fourth ring of product pins 4 using bonding wires 17. An adhesive film is then applied to the back of the frame, followed by molding with molding compound 16. After molding, the frame is cured, then tinned, and then printed. The second supporting entity connecting rib 10 is removed along the first cutting path 18 during the first cut, separating the third ring of product pins 3 and the fourth ring of product pins 4 to form independent signals for each pin. Finally, the first supporting entity connecting rib is removed during the second cut, separating the first ring of product pins and the second ring of product pins.

[0014] By adopting this invention, the number of pins can be doubled or more while maintaining the same product area by changing the pin arrangement, thereby enabling the transmission of more signals. This allows the product to quickly transmit signals at the application end, stabilize product performance, and meet customer usage standards. It possesses excellent physical characteristics such as high temperature resistance, high voltage resistance, high frequency, and high power, bringing significant system advantages to industrial applications in terms of improved energy efficiency, system miniaturization, and increased voltage resistance. Its application prospects are very broad. Furthermore, with the maturity of mass production technology, large-size, high-pin-area, multi-turn QFN products will become the mainstream semiconductor product in the future, applied in consumer electronics, data centers, 5G base stations, new energy vehicles, and many other fields. The improved performance of multi-turn, high-pin-area, pinless QFN semiconductor devices is the driving force behind the improvement of power system performance in terms of power density, power efficiency, operating frequency, and reliability. Moreover, the inherent characteristics of the multi-turn, high-pin-area, pinless QFN product framework structure determine that multi-turn, high-pin-area, pinless QFN devices have advantages such as high conduction signal density, high output power density, good switching recovery characteristics, high heat dissipation power efficiency, and excellent high-temperature operating characteristics. The multi-turn high-pin leadless QFN product frame structure enables efficient and reliable packaging of multi-turn QFN products.

[0015] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0016] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-turn, high-pin, leadless QFN product frame structure, characterized in that: It includes: The frame base island includes the base island body, the base island edge ground wire ring, and the base island support reinforcement; First ring of product pins; Second ring of product pins; And the third ring of product pins; The outer periphery of the frame base island is provided with a base island edge grounding ring. At the four corners of the base island edge grounding ring, obliquely arranged guide strips are respectively provided. The outer ends of adjacent guide strips are connected by a first supporting entity connecting rib. The first supporting entity connecting rib is provided with a first ring of product pins and a second ring of product pins arranged at intervals. At least one outwardly protruding base island supporting connecting rib is arranged on each side of the base island edge grounding ring. Parallel second supporting entity connecting ribs are arranged on the outer side of each side of the base island edge grounding ring. The four second supporting entity connecting ribs enclose and form a rectangular arrangement. Each second supporting entity connecting rib is arranged with a third ring of product pins protruding inward or outward.

2. The multi-turn high-pin leadless QFN product frame structure according to claim 1, characterized in that: It also includes a fourth ring of product pins, with a third ring of product pins arranged outwards on each of the second support entities connecting ribs, and a fourth ring of product pins arranged inwards on each of the second support entities connecting ribs.

3. The multi-turn high-pin leadless QFN product frame structure according to claim 2, characterized in that: A base island support rib protrudes outward from the center of the length direction of each side of the base island edge ground wire ring. The outer end of the base island support rib is fixed to the center of the length direction of the second support entity rib at the corresponding position. The position of the base island support rib does not conflict with the position of the fourth ring of product pins.

4. The multi-turn high-pin leadless QFN product frame structure according to claim 2, characterized in that: The back edge of the frame island is designed with anti-overflow steps, and rectangular through holes are set at intervals on the anti-overflow steps. The outer periphery of the rectangular through holes is the grounding ring of the island edge.

5. The multi-turn high-pin leadless QFN product frame structure according to claim 2, characterized in that: The position of the first ring of product pins corresponding to the first supporting entity connecting rib protrudes outward from the position of the second ring of product pins, and the third ring of product pins and the fourth ring of product pins are respectively provided on both sides of the second supporting entity connecting rib.

6. The multi-turn high-pin leadless QFN product frame structure according to claim 1, characterized in that: The front sides of the first ring of product pins and the second ring of product pins are respectively provided with front half-etched structures, and the back sides of the front ends of the first ring of product pins and the second ring of product pins are respectively provided with back half-etched structures.

7. A packaging method for a multi-turn, high-pin, leadless QFN product frame, characterized in that, The process involves prefabricating a multi-ring high-pin leadless QFN product frame structure as described in any one of claims 1-6, then thinning the chipset and dicing it, placing the chip on the base island body to complete the chip mounting, then bonding the chip and the corresponding product pins of each ring using bonding wires, then applying an adhesive film to the back of the frame, followed by plastic encapsulation, curing after plastic encapsulation, then tinning, and then printing. A first cut is made along the first cut path to remove the connecting ribs of the second support entity, separating the product pins of the third and fourth rings to form independent signals for each pin. Finally, a second cut is made to remove the connecting ribs of the first support entity, separating the product pins of the first and second rings.

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