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Method for regulating and controlling orientation of Sn grains in micro welding spots in multiple reflow processes

A technology of grain orientation and micro-soldering, applied in welding equipment, auxiliary devices, circuits, etc., can solve the problems of lack of continuity and consistency, and achieve the effect of convenient manufacturing process, good consistency, and improved service life

Active Publication Date: 2021-02-09
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] According to the technical problem that the Sn grain structure of the micro-soldering joint lacks continuity and consistency between different reflow processes, a method for regulating the Sn grain orientation of the micro-soldering joint during multiple reflow processes is provided.

Method used

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  • Method for regulating and controlling orientation of Sn grains in micro welding spots in multiple reflow processes
  • Method for regulating and controlling orientation of Sn grains in micro welding spots in multiple reflow processes
  • Method for regulating and controlling orientation of Sn grains in micro welding spots in multiple reflow processes

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Embodiment 1

[0052] Such as Figure 1-5 Shown, in a kind of multiple reflow process of the present invention, the method for regulating and controlling micro-soldering spot Sn crystal grain orientation can be realized by following specific process step:

[0053] Step 1: providing a first substrate 1, and electroplating on the first substrate 1 an array of 20×30 Cu first metal pads 2 with a thickness of 50 μm, on the prepared Cu first metal pads 2 The first solderable layer 3 of Ni / Au is prepared by sputtering, and SnAgCu solder balls are planted on the first solderable layer 3 of Ni / Au and reflowed to make SnAgCu solder micro bumps 7 with a thickness of 100 μm; Substrate 4, prepare 20×30 arrays of Cu second metal pads 5 with a thickness of 50 μm by electroplating on the second substrate 4, and chemically deposit OSP (Organic Solderability Preservatives) on the prepared Cu second metal pads 5 ) second solderable layer 6; coating rosin flux 8 on the surface of OSP second solderable layer 6;...

Embodiment 2

[0060] Such as Figure 1-4 and Figure 6 Shown, in a kind of multiple reflow process of the present invention, the method for regulating and controlling the micro-soldering point Sn crystal grain orientation can be realized by following specific process step:

[0061] Step 1: providing a first substrate 1, electroplating on the first substrate 1 an array of 20×30 Cu first metal pads 2 with a thickness of 10 μm, on the prepared Cu first metal pads 2 The first solderable layer 3 of Ni / Au is prepared by sputtering, and SnAgCu solder balls are planted on the first solderable layer 3 of Ni / Au and reflowed to make SnAgCu solder micro bumps 7 with a thickness of 100 μm; Substrate 4, preparing 20×30 arrays of Cu second metal pads 5 with a thickness of 50 μm by electroplating on the second substrate 4, and chemically depositing OSP second metal pads 5 on the prepared Cu second metal pads 5 Welding layer 6; Coating rosin flux 8 on the surface of OSP second solderable layer 6;

[0062...

Embodiment 3

[0068] Such as Figure 1-4 Shown, in a kind of multiple reflow process of the present invention, the method for regulating and controlling micro-soldering spot Sn crystal grain orientation can be realized by following specific process step:

[0069] Step 1: providing a first substrate 1, electroplating on the first substrate 1 an array of 20×30 Cu first metal pads 2 with a thickness of 10 μm, on the prepared Cu first metal pads 2 The first solderable layer 3 of Ni / Au is prepared by sputtering, and SnAgCu solder balls are planted on the first solderable layer 3 of Ni / Au and reflowed to make a SnAgCu solder micro bump 7 with a thickness of 50 μm; Substrate 4, preparing 20×30 arrays of Cu second metal pads 5 with a thickness of 60 μm by electroplating on the second substrate 4, and chemically depositing OSP second metal pads 5 on the prepared Cu second metal pads 5 Welding layer 6; Coating rosin flux 8 on the surface of OSP second solderable layer 6;

[0070] Step 2: aligning t...

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Abstract

The invention provides a method for regulating and controlling the orientation of Sn grains in micro welding spots in multiple reflow processes. The method is characterized in that a preset reflow technology is adopted to carry out two or more times of brazing reflow on a combination structure formed by a first metal bonding pad with brazing filler metal micro bumps, and a second metal bonding padwhich are arranged between a first substrate and a second substrate, and after each brazing reflow process, the brazing filler metal is completely solidified to form the micro welding spots, so thatthe Sn grains in the micro welding spots have preferred orientation or texture characteristics. According to the method, corresponding technological parameters are changed during the second brazing reflow process, regulation and control over the orientation of the Sn grains in the brazing filler metal matrix of the micro welding spots are achieved, preferentially-oriented micro welding spots are formed, the first substrate and the second substrate are mutually connected, the manufacturing process is convenient, good compatibility with the multiple-brazing reflow technology in a semiconductor and packaging technology is achieved, the formed preferentially-oriented micro welding spots have good reliability resistant to electromigration and thermal migration, and the service life of the microwelding spots or a device with the material structure and structural characteristics is prolonged.

Description

technical field [0001] The invention relates to the technical field of electronic manufacturing, in particular to a method for regulating and controlling the Sn crystal grain orientation of micro solder joints in multiple reflow processes. Background technique [0002] With the continuous development of electronic packaging devices towards multi-function, high performance and small volume, electronic packaging technology has also developed from 2D packaging to 3D packaging, which is characterized by lightness, thinness, small size, high density, high speed and low cost. Under the development trend of miniaturization, the size of micro-solder joints that carry power supply, heat dissipation, and mechanical support continues to decrease. Micro-solder joints usually use Sn-based solder as the connecting material. Only a few or even a single β-Sn grain is formed in the solder joint. β-Sn is an allotrope of metal Sn, the crystal structure is a body-centered tetragonal structure ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K1/00B23K3/08B23K101/40
CPCB23K1/0008B23K3/08B23K3/085B23K2101/40
Inventor 赵宁乔媛媛马海涛
Owner DALIAN UNIV OF TECH