A lead frame structure for preventing base island deformation

Abstract

The utility model discloses a lead frame structure of preventing base island deformation, including frame main part, and frame main part includes upper edge, lower edge and a plurality of vertical muscle, and is equipped with a plurality of equal interval distribution's encapsulation unit on every vertical muscle, the encapsulation unit includes base island and lead pin, and lead pin is divided into first lead pin, second lead pin, third lead pin and fourth lead pin, and base island is linked with fourth lead pin, the middle of base island is equipped with open area, and base island both sides are connected through first connecting rib and are adjacent base island or upper edge or lower edge. The utility model discloses the frame utilization maximization, and the production capacity is improved significantly, and effectively satisfies the large -scale production demand, sets up the open area on the base island, can effectively buffer the impact force of molten material in MD process, reduces the die flow pressure, and the phenomenon of the punch bending, punch line of line arc in WB technology because of pressure impact is reduced significantly, and base island is fixed in two -sided connecting rib bidirectionally, and the anti -deformation ability is improved, and effectively avoid the problem of welding position deviation and virtual welding.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor packaging technology, and in particular to a lead frame structure that prevents base island deformation. Background Technology

[0002] In the semiconductor packaging field, the structural design of the SiP (System-in-Package) framework plays a crucial role in product performance, manufacturing efficiency, and reliability. Currently, traditional SiP4 product frameworks (such as...) Figure 5 As shown, the following technical bottlenecks are commonly present:

[0003] 1. Existing SIP4 frames mostly adopt a single-row design, with typical dimensions of 221.91×22.09mm, containing only 1 column of 30 rows of 30EA units. The frame space is not fully utilized, resulting in low output per processing cycle, which is difficult to meet the ever-increasing production capacity demand.

[0004] 2. The traditional frame uses a large-area base island structure. In the WB (wire bonding) process, the long arc distance is easily affected by the mold flow pressure, resulting in arc bending or even wire breaking. This not only affects heat dissipation efficiency but may also lead to electrical connection failure.

[0005] 3. In the existing framework, the traditional base island 5 generally adopts a single rib design. The traditional base island 5 is not sufficiently supported in the DA (chip mounting) and WB processes, and is prone to deformation, which in turn causes defects such as wire bonding position misalignment and cold solder joints, affecting operation efficiency and product yield. Utility Model Content

[0006] To address the aforementioned issues, this invention provides a lead frame structure that prevents base island deformation, resulting in high production efficiency, reduced wire breakage probability during wire bonding, and improved product yield.

[0007] Therefore, the technical solution of this utility model is: a lead frame structure for preventing base island deformation, comprising a frame body, the frame body including an upper rib, a lower rib and several vertical ribs, each vertical rib having several equidistantly distributed encapsulation units; the encapsulation unit includes a base island and pins, the pins being divided into a first pin, a second pin, a third pin and a fourth pin, the base island being connected to the fourth pin; the base island has a hollow area in the middle, and the two sides of the base island are connected to adjacent base islands or upper ribs or lower ribs through a first connecting rib.

[0008] Based on the above scheme and as a preferred embodiment of the above scheme: the base island has a first U-shaped opening on the side away from the pin and a second U-shaped opening on the side facing the pin, the first U-shaped opening and the second U-shaped opening constitute the hollow area of ​​the base island.

[0009] Based on the above scheme and as a preferred scheme: the middle base island is connected to the adjacent base island on both sides by the first connecting bar, and the base island on one side at the edge of both sides is connected to the adjacent base island by the first connecting bar, and the other side is connected to the upper or lower bar by the first connecting bar.

[0010] Based on the above scheme and as a preferred embodiment of the above scheme: the first pin, the second pin, the third pin and the fourth pin are connected to the upper rib and the lower rib through the second connecting rib.

[0011] Based on the above scheme and as a preferred embodiment of the above scheme: the encapsulation units within the frame body are evenly distributed in rows and columns, with 10 rows and 10 columns.

[0012] Based on the above scheme and as a preferred embodiment of the above scheme: the vertical ribs are divided into side vertical ribs and middle vertical ribs. The side vertical ribs are provided with a row of encapsulation units on one side, and the middle vertical ribs are provided with a row of encapsulation units on each side.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. The packaging units within the frame body adopt a matrix structure with 10 rows and 10 columns evenly distributed. Compared to the traditional single-column 30EA design, 100EA units can be produced in a single MD (molding) cycle, maximizing frame utilization, significantly improving production capacity, and effectively meeting the needs of large-scale production. Simultaneously, one column of packaging units is set on each side of the side vertical ribs, and one column of units is set on each side of the central vertical rib. This symmetrical layout eliminates the space waste of the traditional single-column design, further improving the output efficiency per unit area.

[0015] 2. A hollowed-out area is incorporated into the substrate island, effectively buffering the impact of molten material during the molding (MD) process, reducing mold flow pressure, and significantly minimizing bending and wire breakage caused by pressure impact during the wire bonding (WB) process, thus lowering the wire bonding defect rate. Simultaneously, the hollowed-out area increases the contact area between the substrate island surface and the air, shortening the heat dissipation path. Compared to traditional large-area substrate island structures, this reduces thermal resistance, meeting the heat dissipation requirements of high-power chips and preventing performance degradation due to overheating.

[0016] 3. The base islands are connected to adjacent base islands or upper and lower side ribs via a first connecting rib, forming a "horizontal + longitudinal" mesh support structure. The base islands are bidirectionally fixed by the connecting ribs on both sides, reducing deformation displacement during DA (die mounting) and WB processes, improving deformation resistance, and effectively preventing solder wire misalignment and cold solder joint issues. Simultaneously, the double-rib structure reduces the risk of fatigue damage to the base islands, reduces the cumulative deformation of the frame during repeated processing (such as punching and forming), extends mold life, and reduces maintenance costs. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the structure of the two-column packaging unit of this utility model;

[0019] Figure 3 This is a schematic diagram of the structure of adjacent packaging units of this utility model;

[0020] Figure 4 This is a schematic diagram of the packaging unit of this utility model;

[0021] Figure 5 This is a schematic diagram of the existing lead frame structure.

[0022] The following are labeled in the diagram: top rib 1, bottom rib 2, side vertical rib 31, middle vertical rib 32, packaging unit 4, base island 41, first pin 42, second pin 43, third pin 44, fourth pin 45, second connecting rib 46, first U-shaped opening 47, second U-shaped opening 48, first connecting rib 49, and traditional base island 5. Detailed Implementation

[0023] In the description of this utility model, it should be noted that the directional terms such as "center", "horizontal (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature. In the description of this utility model, "several" or "a number" means two or more, unless otherwise explicitly specified.

[0025] See the attached diagram. The lead frame structure described in this embodiment is a SIP-4L-THIN frame, which follows the SIP-4L-DA frame design specification and uses the Matrax design for connection. The Matrax design improves the utilization rate of the frame. The main body of the frame has dimensions of 268*68.82mm. The main body of the frame includes an upper rib 1, a lower rib 2, and several vertical ribs. The vertical ribs are divided into side vertical ribs 31 and middle vertical ribs 32. Each side vertical rib 31 has a row of encapsulation units 4 on one side, and each middle vertical rib 32 has a row of encapsulation units 4 on both sides. There are a total of 2 side vertical ribs 31 and 4 middle vertical ribs 32. Thus, the encapsulation units 4 in the frame body 1 are evenly distributed in rows and columns, with a total of 10 rows and 10 columns, for a total quantity of 100. Compared with the traditional single-row 30EA design, 100EA units can be produced in a single molding, maximizing the frame utilization rate, significantly improving production capacity, and effectively meeting the needs of large-scale production.

[0026] The packaging unit 4 includes a base island 41 and pins. The pins are divided into a first pin 42, a second pin 43, a third pin 44, and a fourth pin 45. The base island 41 is connected to the fourth pin 45. The first pin 42, the second pin 43, the third pin 44, and the fourth pin 45 are connected to the upper rib 1 and the lower rib 2 through a second connecting rib 46. The base island 41 has a first U-shaped opening 47 on the side away from the pins and a second U-shaped opening 48 on the side facing the pins. The first U-shaped opening 47 and the second U-shaped opening 48 form a hollow area of ​​the base island, which can effectively buffer the impact force of molten material during the MD (molding) process, reduce the mold flow pressure, significantly reduce the bending and wire punching phenomena caused by pressure impact in the WB process, and reduce the wire bonding defect rate.

[0027] Each row of base islands 41 includes edge base islands and eight intermediate base islands. The intermediate base islands are connected to adjacent base islands on both sides by first connecting ribs 49. The edge base islands on one side are connected to adjacent base islands by first connecting ribs 49, and the other side is connected to upper rib 1 or lower rib 2 by first connecting ribs 49. The base islands are bidirectionally fixed by the connecting ribs on both sides, which reduces the deformation displacement of the base islands in DA (die mounting) and WB processes, improves the resistance to deformation, and effectively avoids the problems of solder wire misalignment and cold solder joints.

[0028] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A lead frame structure for preventing base island deformation, comprising a frame body, the frame body including an upper rib, a lower rib, and a plurality of vertical ribs, characterized in that: Each vertical rib is provided with several equidistantly distributed encapsulation units; the encapsulation unit includes a base island and pins, the pins are divided into a first pin, a second pin, a third pin and a fourth pin, the base island is connected to the fourth pin; the base island has a hollow area in the middle, and the two sides of the base island are connected to adjacent base islands or upper or lower ribs through a first connecting rib.

2. The lead frame structure for preventing base island deformation as described in claim 1, characterized in that: The base island has a first U-shaped opening on the side away from the pin and a second U-shaped opening on the side facing the pin. The first U-shaped opening and the second U-shaped opening constitute the hollow area of ​​the base island.

3. The lead frame structure for preventing base island deformation as described in claim 1, characterized in that: The middle base island is connected to the adjacent base island on both sides by the first connecting bar. At the edge of both sides, one side of the base island is connected to the adjacent base island by the first connecting bar, and the other side is connected to the upper or lower bar by the first connecting bar.

4. The lead frame structure for preventing base island deformation as described in claim 1, characterized in that: The first pin, the second pin, the third pin, and the fourth pin are connected to the upper and lower ribs via the second connecting rib.

5. The lead frame structure for preventing base island deformation as described in claim 1, characterized in that: The encapsulation units within the frame body are evenly distributed in rows and columns, with 10 rows and 10 columns.

6. The lead frame structure for preventing base island deformation as described in claim 1, characterized in that: The vertical ribs are divided into side vertical ribs and middle vertical ribs. The side vertical ribs have a row of encapsulation units on one side, and the middle vertical ribs have a row of encapsulation units on each side.

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