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Ultrathin pre-plating layer lead frame and preparation method thereof

A lead frame and pre-plating technology, used in semiconductor/solid-state device manufacturing, electrical components, electrical solid-state devices, etc., can solve problems such as solder joint embrittlement, hidden reliability concerns, and cost increase, and achieve reduced thickness and low diffusion rate. , increase antioxidant effect

Inactive Publication Date: 2011-06-15
GUANGZHOU HKUST FOK YING TUNG RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the cost also increases
In addition, the increase in the thickness of the Au / Pd layer can also cause embrittlement of the solder joint, and the thick nickel metal layer is easy to break when bent, which are hidden concerns for reliability.
[0003] In this way, it is technically faced with the challenge of how to reduce the thickness of the Au / Pd / Ni layer to save costs while maintaining or even improving the quality and reliability of the lead frame

Method used

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  • Ultrathin pre-plating layer lead frame and preparation method thereof
  • Ultrathin pre-plating layer lead frame and preparation method thereof
  • Ultrathin pre-plating layer lead frame and preparation method thereof

Examples

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Embodiment 1

[0039] Such as figure 1 Shown ultra-thin pre-plating lead frame is embodiment one of the present invention, and it comprises copper alloy lead frame substrate 1, on this substrate, tin (Sn) metal layer 2, nickel (Ni) metal layer 3, palladium ( Pd) metal layer 4 and gold (Au) metal layer 5 .

[0040] In this embodiment, the thickness of the Sn metal layer is 3 nm, the thickness of the Ni metal layer is 250 nm, the thickness of the nanoscale Pd metal layer is 10 nm, and the thickness of the nanoscale Au metal layer is 2 nm.

[0041] In practical applications, the thickness of the Sn metal layer can be selected arbitrarily in the range of 1-10nm, the thickness of the Ni metal layer can be selected in the range of 50-350nm, and the thickness of the Pd metal layer can be selected in the range of 5-15nm. Selection; the thickness of the Au metal layer can be properly selected within the range of 1-10 nm.

Embodiment 2

[0043] Such as figure 2 The ultra-thin pre-plating lead frame shown is embodiment two of the present invention, and it comprises copper alloy lead frame substrate 1, on this substrate, first nickel (Ni) metal layer 6, tin (Sn) metal layer 2, tin (Sn) metal layer 2, A second nickel (Ni) metal layer 3 , a palladium (Pd) metal layer 4 and a gold (Au) metal layer 5 .

[0044]In this embodiment, the thickness of the first Ni metal layer 6 is 50nm, the thickness of the Sn metal layer is 3nm, the thickness of the second Ni metal layer 3 is 200nm, the thickness of the Pd metal layer is 10nm, and the thickness of the Au metal layer is 2nm .

[0045] In practical application, the thickness of the first Ni metal layer 6 can be selected arbitrarily in the range of 0-200nm, the thickness of the second Ni metal layer can be selected in a suitable value in the range of 50-350nm; the thickness of the Sn metal layer can be in the range of 1 The thickness of the Pd metal layer can be selecte...

Embodiment 3

[0047] Embodiment 3 of the present invention is a method for preparing a lead frame by high-frequency pulse electrodeposition to prepare the pre-coating structure described in Embodiments 1 and 2, specifically comprising:

[0048] 1) Activate the copper alloy lead frame substrate: first soak the lead frame in 8%-20% sulfuric acid solution for 10-30s, then rinse with deionized water; then immerse the lead frame in 8%-20% sulfuric acid solution In the hydrochloric acid solution, the soaking time is 10-30s, then washed with deionized water and then dried for electrodeposition treatment.

[0049] 2) Sn metal layer electroplating solution and electroplating process: the working frequency of the high-frequency pulse electricity used is 200Hz-500Hz, and the current density is 0.1-2A / dm 2 , the duty ratio used is 30%-60%; the plating solution used is composed of stannous methanesulfonate 10-40g / L, stannous sulfate 20-40g / L, cresolsulfonic acid 30-50g / L, sulfuric acid 10~20g / L, 0.1~0....

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Abstract

The invention relates to an ultrathin pre-plating layer lead frame (PPF) which comprises the following two structures: (1) a high texture copper alloy substrate lead frame is sequentially and electrically deposited with a tin metal layer, a nickel metal layer, a palladium metal layer and an aurum metal layer; (2) the high texture copper alloy substrate lead frame is sequentially and electrically deposited with a nickel metal layer, a tin metal layer, a nickel metal layer, a palladium metal layer and an aurum metal layer. Due to interdiffusion reaction, Cu-Sn-Ni or Ni-Sn intermetallic compound(IMC) can be formed in situ and effectively prevents copper from diffusing outwards and being oxidized; by combining the quasi-epitaxial pulse plating process, the ultrathin pre-plating layer lead frame is obtained, and the antioxidation and the corrosion resistant performance of the lead frame are improved; furthermore, the technical mode of preventing corrosion by plating thick metal layers such as Ni metal layer and the like is replaced by the invention, so that the thickness of Ni / Pd / Au can be effectively reduced, and the cost is lowered.

Description

technical field [0001] The invention belongs to the field of lead-free electronic packaging, and in particular relates to an ultra-thin pre-coated lead frame structure and a preparation process thereof. The invention proposes two pre-coated lead frame (PPF) structures, and the invention also relates to a process method for preparing quasi-epitaxy-grown ultra-thin pre-coated lead frame by high-frequency pulse current electrodeposition. Background technique [0002] A pre-plated leadframe (PPF for short) is an important component of a semiconductor device. It provides support for semiconductor chips and connects chips and wiring boards. The electroplated lead frame with Cu alloy as the lead frame substrate is electroplated with Ni, Pd and Au layers sequentially, which has been widely used. The Ni layer can provide oxidation and corrosion resistance to the lead frame. This is because the Ni layer can prevent the outdiffusion of Cu to the surface of the lead frame, and the ou...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L23/495H01L21/48
CPCH01L2924/0002
Inventor 刘立林张统一
Owner GUANGZHOU HKUST FOK YING TUNG RES INST
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