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A method for restraining tin whisker growing based on micro-nano cone structure

A structure suppression, micro-nano technology, applied in the plating, coating, circuit and other directions of the superimposed layer, can solve the problems such as the thermodynamic driving force cannot be eliminated, the general applicable mechanism is not formed, and the bridge is not formed. The effect of disengagement and reduction of driving force

Inactive Publication Date: 2017-05-17
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Reflow or annealing can increase the incubation period of tin whiskers and delay the formation of tin whiskers, but its thermodynamic driving force cannot be eliminated, and the generation of liquid phase may cause collapse and bridging
[0005] It can be seen that although there are various methods for suppressing tin whiskers, there are still many problems, and a universally applicable mechanism and simple and effective suppression method have not yet been formed.

Method used

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  • A method for restraining tin whisker growing based on micro-nano cone structure
  • A method for restraining tin whisker growing based on micro-nano cone structure

Examples

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Embodiment 1

[0036] Select the lead frame C194 copper alloy as the conductive substrate, degrease the conductive substrate for 20s, the degreasing temperature is 40°C, the degreasing current is 3ASD (A / dm2), after cleaning with deionized water, wash with 20% dilute sulfuric acid for 20s, and then Rinse with deionized water; place the cleaned target substrate in the prepared plating solution at a temperature of 55°C, chemically deposit micron copper needles on the conductive substrate for 20 minutes, and obtain a copper needle structure with a length of about 5 μm. After cleaning with deionized water, put it in the nickel-plated needle plating solution, the solution temperature is 50°C, the current density is 1.2ASD, the plating time is 10min, and the nickel nano-micro cone with a length of about 500nm is obtained by electrodeposition on the micron copper needle. structure. Utilize 20% dilute sulfuric acid to pickle the obtained micro-nano needle cone structure to remove the oxide layer tha...

Embodiment 2

[0038] Select stainless steel as the conductive substrate, degreasing the conductive substrate for 30s, degreasing temperature 40°C, degreasing current 4ASD (A / dm2), after cleaning with deionized water, wash with 20% dilute sulfuric acid for 20s, and then rinse with deionized water Clean; placed in the nickel-plated needle plating solution, the solution temperature is 50°C, the current density is 1.0ASD, the electrodeposition time is 20min, and the nickel nanocone structure with a length of about 700nm is obtained by electrodeposition. Utilize 20% dilute sulfuric acid to pickle the obtained micro-nano needle cone structure to remove the oxide layer that may be exposed to the air, and then place it in a tin plating solution. The temperature of the plating solution is 25 ° C, and the current density is 1.2ASD. The electroplating time is 5 minutes, the thickness of the tin layer is about 2 μm, and the tin layer is cleaned and dried after electroplating.

Embodiment 3

[0040]Select semiconductor silicon as the substrate, first sputter a layer of 50 / 500nm Cr / Cu seed layer on the silicon substrate, wash it with 20% dilute sulfuric acid for 20s, and then rinse it with deionized water; place it in the nickel-plated needle plating solution, The temperature of the solution is 50° C., the current density is 1.0ASD, and the electrodeposition time is 20 minutes. A nickel nanocone structure with a length of about 700 nm is obtained by electrodeposition. Utilize 20% dilute sulfuric acid to pickle the obtained micro-nano needle cone structure to remove the oxide layer that may be exposed to the air, and then place it in a tin plating solution. The temperature of the plating solution is 25 ° C, and the current density is 1.2ASD. The electroplating time is 5 minutes, the thickness of the tin layer is about 2 μm, and the tin layer is cleaned and dried after electroplating.

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Abstract

The invention discloses a method for restraining tin whisker growing based on a micro-nano cone structure. The method comprises the following steps that a conductive matrix is selected and cleaned; after the matrix is cleaned, a micro-nano cone structure layer grows on the conductive matrix; then the micro-nano cone structure layer is cleaned, and a surface oxide layer is removed; and finally, tin-based welding flux grows on the micro-nano cone structure layer. According to the method, the pressure stress in a tin cladding layer is released by utilizing the fact that the micro-nano cone structure layer has a large specific surface area and a unique geometrical shape, driving force for tin cladding layer tin cladding layer is reduced, and formation of tin whisker is restrained; the method is suitable for growing of various types of tin layer thin films and has the advantages that the preparation method is simple, the temperature is low, compatibility of the technique is high, stability is high, and growing of tin whiskers can be effectively restrained.

Description

technical field [0001] The invention belongs to the technical field of electronic packaging materials, and in particular relates to a method for suppressing the growth of tin whiskers based on a micro-nano needle cone structure. Background technique [0002] Because tin (Sn) and tin-based alloys have good oxidation resistance, corrosion resistance and solderability, tin coatings are widely used in the entire electronics industry, especially with the gradual maturity of electroplating tin technology, tin solder is used It is widely used in the field of electronic packaging. However, the electroplated tin coating is prone to grow tin whiskers, which can lead to short circuit of electronic devices and system failure, seriously affecting the reliability of electronic devices. [0003] In the past few decades, there have been endless reports of failure accidents caused by tin whiskers, involving aerospace, nuclear power plants, power plants, satellite radar communications and ot...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/10C25D5/12C25D7/00C25D7/12C23C28/02
CPCC23C28/021C23C28/023C25D5/10C25D5/12C25D7/00C25D7/12
Inventor 胡安民凌惠琴孙梦龙龙晓萍董梦雅胡丰田
Owner SHANGHAI JIAO TONG UNIV
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