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Surface nucleation method for inhibiting Cu/Sn welding spot structure Cu3Sn

A nuclear method and solder joint technology, applied in the field of intermetallic compound material processing, can solve the problems of bridging short circuit between solder joints and extremely strict requirements for effective connection performance of solder joints.

Active Publication Date: 2021-07-30
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, when the bump pitch of Cu / Sn solder joints is reduced to the micro level, the high-density interconnection has extremely strict requirements on the effective connection performance of the solder joints. During the working process, the intermetallic compound Cu 3 The nucleation and growth of Sn along the lateral side wall can easily lead to problems such as bridging between solder joints and short circuits, so solder bumps are facing technical challenges

Method used

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  • Surface nucleation method for inhibiting Cu/Sn welding spot structure Cu3Sn
  • Surface nucleation method for inhibiting Cu/Sn welding spot structure Cu3Sn
  • Surface nucleation method for inhibiting Cu/Sn welding spot structure Cu3Sn

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Embodiment 1

[0022] A method for suppressing Cu / Sn solder joint structure described in the present embodiment Cu 3 The surface nucleation method of Sn adopts plasma chemical vapor deposition (PCVD) to deposit Si powder on the surface of Cu / Sn solder joints in a PCVD furnace to form a dense and firm Si-rich deposition layer. The specific process is as follows: SiCl with a purity of 99.0% 4 The gas is passed into the PCVD furnace as the coating source, and the dilution gas is high-purity Ar gas, SiCl 4 The volume concentration is 10%; the output DC current of the PCVD furnace is 10A, the output DC voltage is 2000V, the deposition pressure is 150Pa, and the deposition temperature is 400°C; a Si layer with a thickness of 10nm is deposited on the surface of a clean Cu / Sn solder joint, which can effectively inhibit the organization of Cu 3 Nucleation of Sn phase, such as image 3 shown.

Embodiment 2

[0024] A method for suppressing Cu / Sn solder joint structure described in the present embodiment Cu 3 The surface nucleation method of Sn adopts plasma chemical vapor deposition (PCVD) to deposit Si powder on the surface of Cu / Sn solder joints in a PCVD furnace to form a dense and firm Si-rich deposition layer. The specific process is as follows: SiCl with a purity of 99.0% 4 The gas is passed into the PCVD furnace as the coating source, and the dilution gas is high-purity Ar gas, SiCl 4 The volume concentration is 30%; the output DC current of the PCVD furnace is 15A, the output DC voltage is 3000V, the deposition pressure is 100Pa, and the deposition temperature is 500°C; a 150nm Si layer is deposited on the surface of a clean Cu / Sn solder joint, which can inhibit the organization of Cu 3 Nucleation of Sn phase, such as Figure 4 shown.

Embodiment 3

[0026] A method for suppressing Cu / Sn solder joint structure described in the present embodiment Cu 3 The surface nucleation method of Sn adopts the vacuum evaporation physical vapor deposition method to deposit Si powder on the surface of Cu / Sn solder joints to form a dense and firm Si-rich deposition layer. The specific process is as follows: Cu / Sn solder joints are cleaned before plating and electrostatic pretreatment; the pretreated Cu / Sn solder joints are loaded into the evaporation coating machine and vacuumed to 1×10 -3 Below Pa, the purity of Si powder for evaporation is 99.999%; the deposition temperature is room temperature, and the deposition rate is 10nm / s; the deposition of 200nm Si layer powder on the surface of the solder joint can completely inhibit the structure of Cu 3 Nucleation of Sn phase, such as Figure 5 shown.

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Abstract

The invention discloses a surface nucleation method for inhibiting a Cu / Sn welding spot structure Cu3Sn, and belongs to the field of intermetallic compound material processing. According to the method, a Si layer with the thickness ranging from 10 nm to 200 nm is deposited on the Cu / Sn surface, surface diffusion of Sn and Cu atoms is prevented, and nucleation of Cu3Sn on the surface is inhibited. According to the method, transverse nucleation and growth of Cu3Sn along the side wall of the Cu / Sn outer surface in the working process can be eliminated, the short circuit danger caused by welding spot bridging in high-density electronic packaging is avoided, the packaging reliability is improved, preparation of small-size welding spots is facilitated, meanwhile, microcracks of a Cu3Sn / brazing filler metal interface can be reduced, and the mechanical property and the electrical and thermal characteristics of the welding spots are remarkably improved.

Description

technical field [0001] The invention relates to a method for suppressing Cu / Sn solder joint structure Cu 3 A Sn surface nucleation method belongs to the field of intermetallic compound material processing. Background technique [0002] With the continuous evolution of micro-nano electronic technology and the continuous upgrading of hardware technology in today's era, the size of microelectronic integrated circuits is getting smaller and higher, and the density is getting higher and higher. At the same time, more complex calculations and processing can be completed on smaller chips. More diversified customization needs. To meet the needs of the rapidly growing market for small, high-performance mobile devices, three-dimensional integrated circuits (3D ICs) have emerged as one of the most promising solutions to achieve shorter interconnections and higher density. In three-dimensional integrated circuit packaging, three different sizes of solder balls are used to achieve ver...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L23/488C23C14/16C23C16/24B23K31/12
CPCH01L24/11H01L24/12C23C14/16C23C16/24B23K31/12H01L2224/1112H01L2224/1145H01L2224/11452H01L2224/11826H01L2224/11827H01L2224/1354H01L2224/136H01L2224/145
Inventor 陈旸陈奉锐郑功祁志祥陈光
Owner NANJING UNIV OF SCI & TECH