CN213988878U

CN213988878U - Novel DFN lead frame

Info

Publication number: CN213988878U
Application number: CN202022941893.3U
Authority: CN
Inventors: 伍江涛; 陈明; 叱晓鹏; 贾家扬; 谯毅
Original assignee: SHENZHEN DIANTONG WINTRONIC MICROELECTRONICS CO Ltd
Current assignee: SHENZHEN DIANTONG WINTRONIC MICROELECTRONICS CO Ltd
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2021-08-17
Anticipated expiration: 2030-12-10

Abstract

The utility model relates to a novel DFN lead frame, including the frame unit of a plurality of arrays, each frame unit includes base island, strengthening rib, cutting way and pin again, the pin includes straight strip district and epitaxial sector area, the pin openly is half silvering and handles, and straight strip district is silvering district, is the second solder joint placement of bonding wire; the extension sector area is an area without silver plating, and the surface is subjected to brown oxidation treatment. The improvement is carried out under the condition that the original base island, the reinforcing ribs and the cutting channels keep the original processing technology unchanged, the problem of layering of pins and plastic package materials is emphasized, the silver coating is important for forming a second welding point and a fishtail of a welding wire, and the silver coating is combined with the material of the welding wire, such as gold, copper and alloy, so that good stability is formed; the surface of the epitaxial sector area is subjected to brown oxidation treatment, the combination effect of the plastic packaging material and the bare copper is obviously better than that of a silver coating, the brown bare copper has better effect, the combination strength of the lead frame and the plastic packaging material can be enhanced, and the method has an active effect on solving the layering problem.

Description

Novel DFN lead frame

Technical Field

The utility model relates to the field of packaging technology, especially, relate to a novel DFN lead frame.

Background

DFN (Dual flat Non-lead Package) is called a rectangular flat Non-lead Package, and can be used in portable consumer electronics products such as notebook computers, digital cameras, Personal Digital Assistants (PDAs), mobile phones, etc. due to its small outline. The DFN lead frame generally comprises four bibliographic categories branch of strengthening rib, base island, pin and cutting way, and this type of packaging body adopts the bottom to leak the metal pad outward as and circuit board connection solder joint, replaces traditional pin, and the metal pad is inside directly to link to each other with the chip at the packaging body simultaneously, and heat conduction and electrically conductive route are shorter, and radiating effect and electrical property homoenergetic obtain obviously promoting. However, the package product is more and more thin in package appearance and lead frame due to the requirements of miniaturization, high performance and the like, and the DFN product is easy to be layered due to the specific cutting and forming process, particularly the pin part of the lead frame, so that the device cannot complete the specified function, and the service life is influenced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a pin and the stronger novel DFN lead frame of plastic envelope material combining ability.

The utility model provides a technical scheme does: a novel DFN lead frame comprises a plurality of arrayed frame units, wherein each frame unit comprises a base island, a reinforcing rib, a cutting channel and a pin, the pin comprises a straight strip area and an extension fan-shaped area, the front surface of the pin is subjected to semi-silvering treatment, and the straight strip area is a silvering area and is a second welding spot of a welding wire; the extension sector area is an area without silver plating, and the surface is subjected to brown oxidation treatment.

The front surface of the extension sector area is of a stepped structure and at least comprises two layers of steps, and the heights of the extension sector area from inside to outside are gradually reduced.

The front surface of the epitaxial sector area comprises five layers of steps, the heights of the steps are sequentially decreased from inside to outside, and the decreasing amplitude is 0.01 mu m.

The utility model has the advantages that: the novel DFN lead frame is improved under the condition that the original base island, the reinforcing ribs and the cutting channels are unchanged in the original processing technology, the problem of layering of pins and plastic packaging materials is emphasized, the front side of each pin is subjected to semi-silvering treatment, a straight strip area is a silvering area and is a second welding spot of a welding line, a large number of experiments prove that a silvered layer is crucial to forming of the second welding spot of the welding line and a fishtail, and the silvered layer is combined with welding line materials such as gold, copper and alloy to form good stability; the epitaxial sector area is an area without silver plating, the surface is subjected to browning treatment (brown oxidation means that the surface roughness can be increased by 0.03 mu m, the bonding performance is improved), the bonding effect of the plastic packaging material and the bare copper is obviously better than that of a silver plating layer, the browned bare copper has a better effect, the bonding strength of a lead frame and the plastic packaging material can be enhanced, and the positive effect on solving the layering problem is achieved.

Drawings

Fig. 1 is a schematic diagram of an embodiment of a novel DFN lead frame of the present invention;

fig. 2 is a schematic diagram of a frame unit of an embodiment of the novel DFN lead frame according to the present invention.

Wherein, 1, a base island; 2. reinforcing ribs; 3. cutting a channel; 4. a pin; 41. a straight strip region; 42. and extending the sector.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As an embodiment of the novel DFN lead frame of the present invention, as shown in fig. 1 and fig. 2, the DFN lead frame comprises a plurality of arrays of frame units, each frame unit further comprises a base island 1, a stiffener 2, a cutting channel 3 and a pin 4, the pin 4 comprises a straight area 41 and an extension sector area 42, the front of the pin 4 is processed by semi-silvering, the straight area 41 is a silvering area, and is a second solder joint drop point of a bonding wire; the epitaxial sector 42 is an un-silvered area, and the surface is browned.

The novel DFN lead frame is improved under the condition that the original base island, the reinforcing ribs and the cutting channels are unchanged in the original processing technology, the problem of layering of pins and plastic packaging materials is emphasized, the front side of each pin 4 is subjected to semi-silvering treatment, the straight strip area 41 is a silvering area and is a second welding point falling point of a welding line, a large number of experiments prove that a silvering layer is important for forming the second welding point and the fishtail of the welding line, and the silvering layer is combined with welding line materials such as gold, copper and alloy to form good stability; the epitaxial sector area 42 is an area without silver plating, the surface is browned (brown oxidation means that the surface roughness can be increased by 0.03 mu m, the bonding performance is improved), the bonding effect of the plastic packaging material and the bare copper is obviously stronger than that of a silver plating layer, the browned bare copper has better effect, the bonding force of the lead frame and the plastic packaging material can be enhanced, and the lamination problem is solved.

Epitaxial sector 42 openly is cascaded structure, includes two layers of ladder at least, and outside height from the inside steadily decreases in proper order. In this embodiment, the front surface of the epitaxial sector region includes five steps, the heights of the five steps decrease progressively from inside to outside, the decreasing amplitude is 0.01 μm, and the bonding force between the pins and the plastic package material can also be improved.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. A novel DFN lead frame comprises a plurality of arrayed frame units, wherein each frame unit comprises a base island, a reinforcing rib, a cutting channel and a pin, and the DFN lead frame is characterized in that the pin comprises a straight strip area and an extension fan-shaped area, the front surface of the pin is subjected to semi-silvering treatment, the straight strip area is a silvering area and is a second welding spot of a welding wire; the extension sector area is an area without silver plating, and the surface is subjected to brown oxidation treatment.

2. The DFN leadframe according to claim 1, wherein the front surface of the extension segment is a step structure comprising at least two steps with decreasing height from inside to outside.

3. The novel DFN lead frame as set forth in claim 2, wherein the front surface of the extension sector comprises five steps with decreasing height from inside to outside, and the decreasing height is 0.01 μm.