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Ultrathin pre-plating layer lead frame and preparation method thereof

A lead frame and pre-coating technology, which is applied in the field of ultra-thin pre-coated lead frame structure and its preparation process, can solve problems such as embrittlement of solder joints, hidden reliability concerns, easy breakage, etc., and achieve reduced thickness and low diffusion rate , increase the effect of antioxidant

Inactive Publication Date: 2010-01-13
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 The ultra-thin pre-plated lead frame shown is the first embodiment of the present invention. It includes a copper alloy lead frame base 1 on which a tin (Sn) metal layer 2, a nickel (Ni) metal layer 3, and a 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 nano-level Pd metal layer is 10 nm, and the thickness of the nano-level Au metal layer is 2 nm.

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

Embodiment 2

[0043] Such as figure 2 The ultra-thin pre-plated lead frame shown is the second embodiment of the present invention. It includes a copper alloy lead frame substrate 1 on which a first nickel (Ni) metal layer 6, a 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 50 nm, the thickness of the Sn metal layer is 3 nm, the thickness of the second Ni metal layer 3 is 200 nm, the thickness of the Pd metal layer is 10 nm, and the thickness of the Au metal layer is 2 nm. .

[0045] In practical applications, the thickness of the first Ni metal layer 6 can be arbitrarily selected in the range of 0 to 200 nm, and the thickness of the second Ni metal layer can be selected in the range of 50 to 350 nm; the thickness of the Sn metal layer can be 1 It is arbitrarily selected within the range of ~10nm, the thickness of the Pd metal layer can be appr...

Embodiment 3

[0047] Example 3 of the present invention is a method for preparing lead frames by high-frequency pulse electrodeposition. Preparation of the pre-plated layer structure described in Examples 1 and 2, specifically includes:

[0048] 1) Activate the copper alloy lead frame matrix: first immerse 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% Soak in hydrochloric acid solution for 10-30s, then rinse with deionized water and blow dry for electrodeposition treatment.

[0049] 2) Sn metal layer electroplating solution and electroplating process: The working frequency of the high-frequency pulsed electricity used is 200Hz-500Hz, and the current density is 0.1-2A / dm 2 , The duty cycle used is 30%-60%; the plating solution used is 10-40g / L stannous methanesulfonate, 20-40g / L stannous sulfate, 30-50g / L cresol sulfonic acid, sulfuric acid 10~20g / L, 4-4'tetramethyldiaminodiphenylmethane 0.1~0.8g / L, gelatin 0.05~...

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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 specifically relates to an ultra-thin pre-plated lead frame structure and a preparation process thereof. The present invention proposes two pre-plated lead frame (PPF) structures. At the same time, the present invention also relates to a process method for preparing a quasi-epitaxially grown lead frame ultra-thin pre-plated layer by high-frequency pulse current electrodeposition. Background technique [0002] Pre-plated leadframe (PPF) is an important part of semiconductor devices. It provides support for the semiconductor chip and connects the chip and the wiring board. The electroplated lead frame with Cu alloy as the lead frame base body sequentially electroplated with Ni, Pd and Au layers has been widely used. The Ni layer can provide oxidation and corrosion resistance for the lead frame. This is because the Ni layer can prevent Cu from diffusing outward to the surface of the l...

Claims

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Application Information

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Patent Type & Authority Applications(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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