Pre-plastic encapsulated wire frame strip and manufacturing method thereof

Abstract

The present invention relates to a pre-molded lead frame strip and a method for manufacturing the same. According to an embodiment of the present invention, the pre-molded lead frame strip has a first surface and a second surface that are opposite to each other. The pre-molded lead frame strip includes a plurality of lead frame units arranged in an array, each lead frame unit including a carrier plate configured to carry a circuit to be packaged, a plurality of pins arranged around the carrier plate, and a pre-molded colloid, wherein the carrier plate is exposed on the first surface of the pre-molded lead frame strip, and a plurality of pins are exposed on the first surface and the second surface of the pre-molded lead frame strip. The embodiment of the present invention can perform performance debugging on a chip through the lead frame unit without destroying the structure of each lead frame unit in the lead frame strip. Moreover, the manufacturing method of the lead frame strip is relatively easy, thereby improving the quality, reliability and qualified rate of the product.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, in particular to a pre-plastic-encapsulated lead frame strip in the field of semiconductor technology and a manufacturing method thereof. Background Art

[0002] In the field of semiconductor technology, the lead frame bar is used as a carrier of the chip, which can electrically connect the chip in the semiconductor package to the external circuit. Therefore, the lead frame bar has a vital impact on the quality of the semiconductor package.

[0003] Before plastic encapsulation, the pins in the traditional lead frame strip are only connected by the connecting ribs on the lead frame strip. If the connecting ribs on the lead frame strip are cut off, all the pins will lose their fixation and the structure of the lead frame strip will be destroyed. However, if the connecting ribs are not cut off, the structure of the lead frame strip can be maintained, but all the pins will be short-circuited, making it difficult to debug the performance of the chip through the lead frame strip. Although some pre-plastic encapsulation technologies can be used to pre-plasticize the lead frame strip to solve the above problems, the electroforming technology is used, which has relatively high cost and production difficulty, and the product yield is low.

[0004] Therefore, the existing pre-plastic-encapsulated lead frame strip and its manufacturing method still need to be further improved. Summary of the invention

[0005] One of the purposes of the present invention is to provide a pre-molded lead frame strip and a manufacturing method thereof, which can solve the technical problem in the prior art that it is difficult to perform performance debugging of a chip through the lead frame strip before molding.

[0006] An embodiment of the present invention provides a pre-molded lead frame strip having a first surface and a second surface opposite to each other. The pre-molded lead frame strip comprises a plurality of lead frame units arranged in an array, each lead frame unit comprises a carrier plate configured to carry a circuit to be packaged, a plurality of pins arranged around the carrier plate, and a pre-molded colloid, wherein the carrier plate is exposed on the first surface of the pre-molded lead frame strip, and a plurality of pins are exposed on the first surface and the second surface of the pre-molded lead frame strip.

[0007] According to another embodiment of the present invention, the pre-molded lead frame strip further comprises a connecting rod connected to the carrier plate and a connecting rib connecting the plurality of pins, and surfaces of the plurality of pins exposed to the second surface have a tin layer.

[0008] One embodiment of the present invention also provides a method for manufacturing a pre-molded lead frame strip, the manufacturing method comprising: providing a lead frame strip, the lead frame strip having a first surface and a second surface relative to each other and comprising a plurality of lead frame units arranged in an array, each lead frame unit comprising a carrier plate configured to carry a circuit to be packaged and a plurality of pins arranged around the carrier plate; applying a film to the first surface of the lead frame strip; pre-molding the second surface of the lead frame; grinding the second surface of the pre-molded lead frame strip until the plurality of pins are exposed on the second surface; and electroplating the plurality of pins exposed on the second surface.

[0009] According to another embodiment of the present invention, the manufacturing method of the pre-molded lead frame strip further includes removing the film on the second surface of the lead frame strip before affixing the film on the first surface; and tearing off the film on the first surface after electroplating the plurality of pins exposed on the second surface.

[0010] According to another embodiment of the present invention, the film on the first surface is a high temperature resistant adhesive film, the electroplating of the plurality of pins exposed on the second surface further includes tin plating on the plurality of pins exposed on the second surface, and each lead frame unit further includes a connecting rod connected to the carrier plate, and connecting ribs connecting the plurality of pins.

[0011] The pre-molded lead frame strip and the manufacturing method thereof provided by the embodiment of the present invention can debug the performance of the chip through the lead frame unit without destroying the structure of each lead frame unit in the lead frame strip. Moreover, the manufacturing method of the lead frame strip is relatively easy, and the quality, reliability and qualified rate of the product are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. 1 is a schematic diagram of a first surface of a pre-molded lead frame strip according to an embodiment of the present invention.

[0013] Figure 2 FIG. 1 is a schematic diagram of the second surface of a pre-molded lead frame strip according to an embodiment of the present invention.

[0014] Figure 3-6 FIG. 1 is a schematic diagram of a manufacturing method of a pre-plastic-encapsulated lead frame strip according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to better understand the spirit of the present invention, it is further described below in conjunction with some preferred embodiments of the present invention.

[0016] Figure 1 and Figure 21 and 2 are schematic diagrams of a first surface 100 and a second surface 101 of a pre-molded lead frame strip 10 according to an embodiment of the present invention, wherein the first surface 100 and the second surface 101 are two opposite surfaces of the pre-molded lead frame strip 10 .

[0017] Combination Figure 1 and Figure 2 According to an embodiment of the present invention, the pre-molded lead frame strip 10 includes a plurality of lead frame units 12 arranged in an array. Due to layout limitations, Figure 1 and 2 Only nine wire frame units 12 arranged in an array are shown. Figure 3-6 Similar. Each lead frame unit 12 includes a carrier plate 102, a connecting rod 103, a plurality of pins 104, a connecting rib 106 and a pre-molded colloid 105. Specifically, the carrier plate 102 is configured to carry a circuit to be packaged (not shown); the connecting rod 103 connects adjacent carrier plates 102 to form an array; a plurality of pins 104 are arranged around the carrier plate 102, and are configured to electrically connect the circuit to be packaged on the carrier plate 102 with external pins (not shown); the connecting rib 106 connects a plurality of pins 104 to maintain the arrangement position of the pins 104, and the pre-molded colloid 105 fills the gaps between the carrier plate 102, the connecting rod 103, the plurality of pins 104 and the connecting rib 106, and partially covers the above components.

[0018] Specifically, by Figure 1 On the first surface 100 of the pre-molded lead frame strip 10 shown, the carrier plate 102, the connecting rod 103, the plurality of pins 104 and the connecting ribs 106 are all exposed on the first surface 100 of the pre-molded lead frame strip 10, that is, the pre-molded colloid 105 is filled between the above components without covering them.

[0019] However, in Figure 2 On the second surface 101 of the pre-molded lead frame strip 10 shown, only a number of pins 104 and a carrier plate 102 are exposed, that is, on the second surface 101 of the pre-molded lead frame strip 10, the connecting rods 103 and the connecting ribs 106 are covered by the pre-molded colloid 105.

[0020] In addition, since the pins 104 are generally made of copper, which is easily oxidized by air, in this embodiment, the surfaces of the pins 104 exposed on the second surface 101 are evenly covered with a tin layer to protect the exposed pins 104 .

[0021] Since the pre-molded lead frame strip 10 in this embodiment has not only connecting ribs 106 but also pre-molded colloid 105 between the plurality of pins 104, when the performance of the chip is debugged through the pre-molded lead frame strip 10, after the connecting ribs 106 are cut off and the short circuit between the plurality of pins 104 is eliminated, the plurality of pins 104 can still maintain their positions and shapes unchanged by being fixed by the pre-molded colloid 105, and the structure of each lead frame unit 12 can also be kept intact.

[0022] Figure 3-Figure 6 1 is a process diagram of a method for manufacturing a pre-molded wire frame strip 10 according to an embodiment of the present invention. The method for manufacturing a pre-molded wire frame strip 10 can manufacture a pre-molded wire frame strip 10 according to an embodiment of the present invention, for example, Figure 1 and Figure 2 The illustrated embodiment is a pre-molded lead frame strip 10 .

[0023] First, a lead frame strip 20 (see Figure 3 ), the lead frame strip 20 has a first surface 200 and a second surface 201 opposite thereto (see Figure 4-6 ), and includes a plurality of wire frame units 22 arranged in an array, wherein each wire frame unit 22 includes a carrier plate 202, a connecting rod 203, a plurality of pins 204, and a connecting rib 206. Specifically, the carrier plate 202 is configured to carry a circuit to be packaged (not shown); the connecting rod 203 connects adjacent carrier plates 202 to form an array; a plurality of pins 204 are arranged around the carrier plate 202, and are configured to electrically connect the circuit to be packaged on the carrier plate 202 with external pins (not shown); the connecting rib 206 connects a plurality of pins 204 to maintain the arrangement position of the pins 204. When a film (not shown) is provided on the second surface 201 of the provided lead frame strip 20, the film on the second surface 201 is removed.

[0024] like Figure 4 As shown, a film 21 is attached to the first surface 200 of the lead frame strip 20 . The film may be a high temperature resistant adhesive film, which can prevent the plastic sealing adhesive used in plastic sealing from overflowing onto the first surface 200 of the lead frame strip 20 .

[0025] Next, the lead frame strip 20 with the film 21 attached is placed into the mold cavity (not shown) with the second surface 201 facing the inside of the mold cavity, and the second surface 201 of the lead frame strip 20 is pre-sealed.

[0026] Afterwards, if Figure 5As shown, the second surface 201 of the pre-molded lead frame strip 20 is ground until a number of pins 204 are exposed on the second surface 201, and then the pins 204 exposed on the second surface 201 are electroplated to prevent them from being oxidized. The electroplating operation can use tin as the electroplating metal.

[0027] like Figure 6 As shown, by tearing off the film 21 on the first surface 200, the Figure 1 and 2 A pre-molded lead frame strip 10 is shown.

[0028] Compared with the traditional lead frame strip design, the pre-molded lead frame strip and the manufacturing method thereof provided by the embodiment of the present invention have the following advantages:

[0029] Firstly, the pre-molded lead frame strip used in the embodiment of the present invention can still maintain the original position and shape of the pins after the connecting ribs are cut off. The traditional lead frame which is unable to perform performance debugging on the chip before molding can achieve performance debugging on the chip before molding through this solution. In addition, the manufacturing method of the pre-molded lead frame strip provided in the embodiment of the present invention can also be used for lead frame strips whose surface does not need to be molded.

[0030] Secondly, without changing the original mass-produced plastic encapsulation mold, the plastic encapsulation and grinding processes in the manufacturing method provided by the embodiment of the present invention are relatively simple, low-cost, and have a short production cycle.

[0031] The technical content and technical features of the present invention have been disclosed as above, but those skilled in the art may still make various substitutions and modifications based on the teachings and disclosures of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to the contents disclosed in the embodiments, but should include various substitutions and modifications that do not depart from the present invention, and are covered by the claims of this patent application.

Claims

1. A pre-molded lead frame strip having an upper surface and a lower surface opposite to each other; the pre-molded lead frame strip comprises a plurality of lead frame units arranged in an array, each lead frame unit comprising: A carrier tray configured to carry the circuit to be packaged; A plurality of pins are arranged around the carrier plate; as well as Pre-molded colloid, The upper surface of the carrier plate is exposed on the upper surface of the pre-molded lead frame strip, and the upper surface and lower surface of the plurality of pins are exposed on the upper surface and lower surface of the pre-molded lead frame strip respectively. 2 . The pre-molded lead frame strip according to claim 1 , further comprising a connecting rod connected to the carrier plate.

3. The pre-molded lead frame strip according to claim 1, further comprising connecting ribs connecting the plurality of pins. 4 . The pre-molded lead frame strip according to claim 1 , wherein the lower surfaces of the plurality of leads have a tin layer.

5. A method for manufacturing a pre-plastic-encapsulated lead frame strip, comprising: A lead frame strip is provided, the lead frame strip having an upper surface and a lower surface opposite to each other and comprising a plurality of lead frame units arranged in an array, each lead frame unit comprising: A carrier tray configured to carry the circuit to be packaged; and A plurality of pins are arranged around the carrier plate; A film is applied on the upper surface of the lead frame strip to cover the upper surface of the carrier plate and the upper surface of the lead to prevent the upper surface of the carrier plate and the upper surface of the lead from being sealed by the plastic sealing body; Pre-sealing the lower surface of the lead frame; Grinding the lower surface of the pre-molded lead frame strip until the lower surfaces of the plurality of pins are exposed on the lower surface; and The lower surface of the plurality of pins exposed on the lower surface is electroplated. 6 . The method for manufacturing a pre-molded lead frame strip according to claim 5 , further comprising removing the film on the lower surface of the lead frame strip before attaching the film on the upper surface.

7. The method for manufacturing a pre-plastic-encapsulated lead frame strip according to claim 5, wherein the film on the upper surface is a high temperature resistant adhesive film. 8 . The method for manufacturing a pre-molded lead frame strip according to claim 5 , wherein the electroplating of the lower surface of the plurality of pins exposed on the lower surface further comprises plating tin on the lower surface of the plurality of pins exposed on the lower surface.

9. The method for manufacturing a pre-molded lead frame strip as claimed in claim 5, further comprising tearing off the film on the upper surface after electroplating the lower surface of the plurality of pins exposed on the lower surface.

10. The method for manufacturing a pre-molded lead frame strip according to claim 5, wherein each of the lead frame units further comprises a connecting rod connected to the carrier plate, and a connecting rib connecting the plurality of pins.

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