Lead frame capable of improving layering

Abstract

According to the lead frame capable of improving layering, the edge of the base island is subjected to wave-shaped treatment, and the bottom of the wave crest is subjected to etching treatment; the side face, close to the base island side, of the pin surrounding the base island is subjected to groove treatment in the direction away from the base island, and the groove is in a hook shape. The edge of a base island for bearing a chip of the lead frame is wavy or further zigzag, so that the glue locking effect is increased under the condition that the overall appearance of a product is not influenced; and in combination with the hook-shaped sawtooth design at the front ends of the pins of the lead frame, the bonding strength of the whole frame and plastic packaging glue is further enhanced, and the lead frame can be suitable for any packaging with base island design / pin design. By adding the metal bumps on the base island, the structure of the lead frame and the plastic package material can be added when the product is subjected to plastic package, and compared with the original plane base island, the side surface of each bump is combined with the plastic package material, so that the combination area is increased, the glue locking effect is achieved again, the product reliability is improved, and the problems of layering and the like are reduced.

Description

Technical Field

[0001] This invention relates to a lead frame, specifically to a lead frame with improved layering, and belongs to the field of semiconductor packaging technology. Background Technology

[0002] With the continuous development of packaging technology, the size of packaged products is also getting larger and larger. The larger the product package size, the larger the base island that carries the chip will be. The bonding between the flat surface of the entire base island and the molding compound is prone to delamination, which affects product performance.

[0003] Leadframes are typically made of metal, which has good conductivity but is rigid, while molding compound is a polymer, which is soft and lacks rigidity. The significant difference in material properties between the two makes gaps prone to appearing when they are joined. On the other hand, the fluctuating external temperature causes the large-area bonding between the two materials to be affected by thermal expansion and contraction to varying degrees, resulting in internal stress. Combined with mechanical vibrations during packaging and transportation, these factors make the interface between the leadframe and the molding compound highly susceptible to delamination.

[0004] To address this issue, it is necessary to provide a lead frame that improves the layering of packaged products. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an improved layered lead frame.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A lead frame for improving layering is provided, with a wavy treatment at the edge of the base island and the bottom of the wave crest is etched out.

[0008] The side of the pin near the base island of the ring base island is grooved away from the base island, and the groove is hook-shaped.

[0009] Several grooves are symmetrically arranged on the same side of the aforementioned pins.

[0010] The trough at the edge of the aforementioned base island is directly opposite the opening of the groove.

[0011] The wavy shape described above can also be serrated.

[0012] The top surface of the aforementioned base island is provided with several protrusions.

[0013] Furthermore, on either side of the base island, the aforementioned protrusions are arranged in parallel; and along the length direction of the protrusion, the end of the protrusion is directly opposite the edge of the base island on that side.

[0014] The advantages of this invention are:

[0015] This invention provides a leadframe for improving delamination. By employing a wavy or serrated design at the edge of the chip-carrying base island, the leadframe enhances adhesive retention without affecting the overall product shape. Combined with the hook-shaped serrated design at the leadframe pin tips, the overall bond strength between the leadframe and the molding compound is further strengthened. This design is applicable to any package with a base island / pin design. By adding metal bumps to the base island, the structure of the leadframe and molding compound is enhanced during product molding. Compared to the original planar base island, each bump's side surface bonds with the molding compound, increasing the bonding area and again providing adhesive retention, thus improving product reliability and reducing delamination issues.

[0016] The present invention provides an improved lead frame for delamination, which has a simple structure and is easy to use. Without affecting the original structure, it improves product reliability, reduces the risk of internal delamination, improves product quality, reduces production line operation risks, and improves operation efficiency. It has strong practicality and wide applicability. Attached Figure Description

[0017] Figure 1 A schematic diagram of the base island structure in the prior art ( Figure 1 'a' is the top view. Figure 1 b is a side view.

[0018] Figure 2 This is a schematic diagram (top view) of the base island structure of the present invention.

[0019] Figure 3 This is a schematic diagram (side view) of the boss structure of the present invention.

[0020] The markings in the attached diagram have the following meanings: 1. Base island, 2. Chip, 3. Heat sink, 4. Pin, 5. Molding compound, 6. Bond wire, 7. Boss. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 The diagram shown is a schematic diagram of the structure of the base island 1 used in the prior art.

[0023] Chip 2 is located on the top surface of base island 1, heat sink 3 is located on the bottom surface of base island 1, and several pins 4 are arranged around base island 1 and connected to chip 2 via bonding wires 6. Figure 1 As shown in Figure a, the four sides of the base island 1, which carries chip 2, are all flat-edged; as shown in Figure a. Figure 1 As shown in b, the sides of the tube pin 4 and the base island 1 facing each other are respectively provided with inward grooves.

[0024] Based on the structure of the base island 1 and pin 4 in the prior art described above,

[0025] This invention applies a wavy or sawtooth shape to the edge of the base island 1, and a semi-etching process can be used to etch away the bottom of the wave crest, such as... Figure 3 As shown; the inward grooves on the sides of pin 4 are made into V-shaped hooks, such as... Figure 2 As shown. Preferably, the groove opening is aligned with the trough of the wave, where the trough is completely eroded.

[0026] like Figure 2 As shown, a bump design is made on the top surface of the base island 1 in an area that does not affect the bonding line 6, and an array of bosses 7 are added. Compared with the original planar base island 1, the side of each boss 7 is bonded to the molding compound 5, increasing the bonding area, increasing the bonding force, and preventing delamination.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. An improved layered leadframe, characterized by, At the edge of the base island, a wave shape is formed, and the bottom of the wave peak is hollowed out; The side of the pin of the ring base island, which is close to the base island, is formed with a groove away from the base island, and the groove is hook-shaped; On the same side of the pin, a plurality of grooves are symmetrically arranged; At the trough of the edge of the base island, the opening of the groove is opposite to the groove.

2. The leadframe of claim 1, wherein, The wave shape can also be zigzag.

3. The leadframe of claim 1, wherein, The top surface of the base island is provided with a plurality of bosses.

4. The leadframe of claim 3, wherein, On either side of the base island, the bosses are arranged in parallel respectively; and along the length direction of the boss, the end of the boss is opposite to the edge of the side base island.

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