High-reliability lead frame structure and manufacturing method thereof

Abstract

The invention provides a high-reliability lead frame structure and a manufacturing method thereof, the lead frame structure comprises a plurality of lead frame units, each lead frame unit comprises a square base island and a plurality of pins arranged at the periphery of the base island, the base island is provided with a chip loading area used for loading a chip, and the chip loading area is provided with a plurality of pins arranged at the periphery of the base island. The periphery of the chip loading area on the base island is provided with a protruding boss, and the side wall of the boss is provided with a through hole. By adopting the lead frame structure provided by the invention, the layering phenomenon after packaging can be prevented, and the packaging reliability is improved.

Description

Technical Field

[0001] The invention relates to the field of integrated circuit packaging, and in particular to a high-reliability lead frame structure and a manufacturing method thereof. Background Art

[0002] The lead frame of an integrated circuit is usually composed of multiple lead frame units. As shown in Figure 1 (a), each lead frame unit includes a base island and multiple pins, and its cross-sectional view is shown in Figure 1 (b). As shown in Figure 2 (a), when packaging an integrated circuit, the chip with the package is usually bonded and fixed on the base island of the lead frame, and then the chip and the pins are connected through internal leads. Finally, the lead frame unit is covered with plastic encapsulation material, and the pins are exposed. Its cross-sectional view is shown in Figure 2 (b).

[0003] As shown in FIG. 1 (b) and FIG. 2 (b), in the lead frame of the prior art, the base island is usually a complete plane, and the molding material and the base island are completely combined by the molecular attraction between the molding material and the base island. There may be insufficient bonding force, resulting in delamination problems between the molding material and the base island. Summary of the invention

[0004] The object of the present invention is to provide a high-reliability lead frame structure and a manufacturing method thereof.

[0005] In an embodiment of the present invention, a high-reliability lead frame structure is provided, which includes a plurality of lead frame units, each lead frame unit includes a square base island and a plurality of pins arranged on the periphery of the base island, the base island has a chip loading area for loading chips, and a raised boss is arranged on the periphery of the chip loading area on the base island, and the side wall of the boss is provided with a through hole. During packaging, the chip is bonded to the chip loading area and connected to the pins through leads, and the plastic packaging material covers the base island, and covers the chip and the boss, and fills the through hole of the boss.

[0006] In the embodiment of the present invention, there are four bosses, which are respectively arranged around the surface of the base island.

[0007] In the embodiment of the present invention, the shape of the boss is a rectangle.

[0008] In the embodiment of the present invention, the through hole is rectangular.

[0009] In an embodiment of the present invention, a method for manufacturing the above-mentioned high-reliability lead frame structure is also provided, which comprises: The first process: etching the lead frame sheet for the first time to obtain a lead frame with a boss; The second process: the lead frame with the boss obtained after etching is subjected to secondary etching to etch the through holes on the side walls of the boss and the base island and pins of the lead frame into shape.

[0010] In the embodiment of the present invention, the first process includes the following steps: Step 1: attaching a mask on the surface of the lead frame plate, wherein the mask has a pattern corresponding to the boss; Step 2: Expose and develop the surface of the plate to be etched, and cover the surface of the plate that does not need to be etched with a mask; Process 3: Etching the exposed plate surface; Step 4: Remove the mask still attached to the surface of the plate after etching to obtain a lead frame with bosses.

[0011] In the embodiment of the present invention, the second process includes the following steps: Step 5: Pasting a mask on the surface of the lead frame having the boss, wherein the mask has a pattern corresponding to the through hole of the boss and the base island and pin of the lead frame; Step 6: The surface of the lead frame that needs to be etched is exposed through exposure and development, and the surface of the lead frame that does not need to be etched is covered with a mask; Step 7: Etching the exposed lead frame surface; Step 8: Remove the mask still attached to the surface of the lead frame after etching to obtain the final lead frame structure.

[0012] Compared with the prior art, the high-reliability lead frame structure of the present invention is provided with a raised boss on the periphery of the chip loading area on the base island, and the side wall of the boss is provided with a through hole. During packaging, the plastic encapsulation material covers the base island, encapsulates the chip and the boss, and fills the through hole of the boss. Through the boss and the through hole, the plastic encapsulation material is more tightly combined with the base island, thereby preventing the occurrence of delamination and improving the reliability of packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1( a ) is a schematic plan view of a lead frame structure in the prior art.

[0014] FIG. 1( b ) is a cross-sectional schematic diagram of a lead frame structure in the prior art.

[0015] FIG. 2( a ) is a plan view of a lead frame structure after packaging in the prior art.

[0016] FIG. 2( b ) is a cross-sectional schematic diagram of a lead frame structure after packaging in the prior art.

[0017] FIG. 3( a ) is a schematic plan view of a lead frame structure according to an embodiment of the present invention.

[0018] FIG3( b ) is a schematic cross-sectional view of a lead frame structure according to an embodiment of the present invention.

[0019] FIG. 4( a ) is a plan view of a lead frame structure after packaging according to an embodiment of the present invention.

[0020] FIG4( b ) is a schematic cross-sectional view of the lead frame structure after packaging according to an embodiment of the present invention.

[0021] Figure 5 It is a schematic diagram of the first stage of the manufacturing process of the lead frame structure of the embodiment of the present invention.

[0022] Figure 6 It is a schematic diagram of the second stage of the manufacturing process of the lead frame structure of the embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] The implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0025] As shown in FIG. 3 (a) and FIG. 3 (b), in an embodiment of the present invention, a high-reliability lead frame structure is provided, which includes a plurality of lead frame units, each of which includes a base island and a plurality of pins arranged on the periphery of the base island. The base island is square, and has a chip loading area for loading chips. It should be noted that in the lead frame, the function of the base island is to load the chip, the area of ​​the base island is usually larger than the area of ​​the chip, and the chip is installed in the central area of ​​the base island. Therefore, the chip loading area is usually the central area of ​​the chip. A raised boss is arranged on the periphery of the chip loading area on the base island, and a through hole is arranged on the side wall of the boss.

[0026] In the embodiment of the present invention, there are four bosses, which are respectively arranged around the surface of the base island. The boss is in a rectangular shape. The through hole is rectangular to facilitate manufacturing and forming. It should be noted that the number, position and shape of the bosses can also be adjusted according to actual needs, and the present invention does not limit them.

[0027] As shown in FIG. 4 (a) and FIG. 4 (b), during packaging, the chip is bonded to the chip loading area of ​​the base island by an adhesive material, and is connected to the pins by wires. The plastic encapsulation material covers the base island and the pins, and covers the chip and the boss, and fills the through hole of the boss. Since the plastic encapsulation material passes through the through hole of the boss during packaging, it is more tightly combined with the base island, preventing the plastic encapsulation material and the base island from being delaminated.

[0028] Furthermore, in an embodiment of the present invention, there is also provided a method for manufacturing the above-mentioned high-reliability lead frame structure, which includes a first process and a second process.

[0029] The first process: the lead frame plate is etched for the first time to obtain a lead frame with a boss.

[0030] The second process: the lead frame with the boss obtained after etching is subjected to secondary etching to etch the through holes on the side walls of the boss and the base island and pins of the lead frame into shape.

[0031] Specifically, Figure 5 As shown, the first process includes the following steps: Step 1: attaching a mask on the surface of the lead frame plate, wherein the mask has a pattern corresponding to the boss; Step 2: Expose and develop the surface of the plate to be etched, and cover the surface of the plate that does not need to be etched with a mask; Process 3: Etching the exposed plate surface; Step 4: Remove the mask still attached to the surface of the plate after etching to obtain a lead frame with bosses.

[0032] Specifically, Figure 6 As shown, the second process includes the following steps: Step 5: Pasting a mask on the surface of the lead frame having the boss, wherein the mask has a pattern corresponding to the through hole of the boss and the base island and pin of the lead frame; Step 6: The surface of the lead frame that needs to be etched is exposed through exposure and development, and the surface of the lead frame that does not need to be etched is covered with a mask; Step 7: etching the exposed lead frame surface to obtain a lead frame structure that meets the requirements; Step 8: Remove the mask still attached to the surface of the lead frame after etching to obtain the final lead frame structure.

[0033] In summary, the high-reliability lead frame structure of the present invention has a raised boss arranged on the periphery of the chip loading area on the base island, and the side wall of the boss is provided with a through hole. During packaging, the plastic encapsulation material covers the base island, encapsulates the chip and the boss, and fills the through hole of the boss. Through the boss and the through hole, the plastic encapsulation material is more tightly combined with the base island, thereby preventing the occurrence of delamination and providing packaging reliability.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high reliability lead frame structure, characterized in that: It comprises a plurality of lead frame units, each of which comprises a square base island and a plurality of pins arranged on the periphery of the base island, the base island having a chip loading area for loading chips, the base island having a raised boss arranged on the periphery of the chip loading area, the side wall of the boss being provided with a through hole, during packaging, the chip is bonded to the chip loading area and connected to the pins through leads, the plastic encapsulation material covers the base island, and covers the chip and the boss, and fills the through hole of the boss.

2. The high reliability lead frame structure according to claim 1, characterized in that: There are four bosses, which are respectively arranged around the surface of the base island.

3. The high reliability lead frame structure according to claim 1, characterized in that: The shape of the boss is a rectangle.

4. The high reliability lead frame structure according to claim 1, characterized in that: The through hole is rectangular.

5. A method for manufacturing a high-reliability lead frame structure according to any one of claims 1 to 4, characterized in that: include: The first process: etching the lead frame sheet for the first time to obtain a lead frame with a boss; The second process: the lead frame with the boss obtained after etching is subjected to secondary etching to etch the through holes on the side walls of the boss and the base island and pins of the lead frame into shape.

6. The method for manufacturing a high-reliability lead frame structure according to claim 5, characterized in that: The first stage of the process includes the following steps: Step 1: attaching a mask on the surface of the lead frame plate, wherein the mask has a pattern corresponding to the boss; Step 2: Expose and develop the surface of the plate to be etched, and cover the surface of the plate that does not need to be etched with a mask; Process 3: Etching the exposed plate surface; Step 4: Remove the mask still attached to the surface of the plate after etching to obtain a lead frame with bosses.

7. The method for manufacturing a high-reliability lead frame structure according to claim 5, wherein: The second process includes the following steps: Step 5: Pasting a mask on the surface of the lead frame having the boss, wherein the mask has a pattern corresponding to the through hole of the boss and the base island and pin of the lead frame; Step 6: The surface of the lead frame that needs to be etched is exposed through exposure and development, and the surface of the lead frame that does not need to be etched is covered with a mask; Step 7: Etching the exposed lead frame surface; Step 8: Remove the mask still attached to the surface of the lead frame after etching to obtain the final lead frame structure.

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