空间辐射环境对电子器件焊点损伤机制及可靠性研究

At present, the study on effects of the soldered joint in electronic device under space radiation as well as high temperature change environment was still blank at home and abroad. The method and content by which investigate the soldered joint in electronic device under space environment are unclear and also lack of related theoretical system and technical basis. Based on the above understanding, the 64 wings QFP joints soldered with the Sn-based, Pb-based, In-based, Au-based solders will be focused as the main object, this proposal aims to explore the conditions of the migration and transformation of elements in the soldered joint under space radiation and vacuum environments, the diffusion, phase transformation and new phase formation of elements in the soldered joint under high temperature change environment, to study radiation damage of heavy charged particles, including irradiation creep, irradiation growth, irradiation hardening and irradiation embrittlement behaviors of vacancy or interstitial atom, to study the influence of the coupling effect on the soldered joints under the condition of the space radiation, vacuum and high temperature change environments by means of numerical simulation, to establish the scientific bases of atom reaction, diffusion mechanism at the joint interface affected by the rays, heat, force, composite energy field as well as vacuum environment, and to build the evaluation method of soldered joint's damage under space environment. It is expected that, in order to meet the needs of “weight loss”, “increase payload ratio” and “microminiaturization of future space vehicle, enhancing the ability to resist radiation and high temperature change of the soldered joint in electronic device, developing the technology of “no active thermal control measures” could be demonstrated after this study.

空间辐射环境对电子器件焊点损伤机制及可靠性研究，国内外尚属空白。有关空间辐射环境对钎焊焊点影响的研究方法和内容极为缺乏。本项目拟以具有代表性的Sn基、Pb基、In基、Au基等钎料合金和64引脚QFP为研究对象，研究空间辐射、真空环境对钎焊焊点元素的迁移及转化、极低温大温变环境过程元素的扩散及相变、新相形成条件；研究焊点界面区组织的重带电粒子辐照损伤，主要包括辐照蠕变、空位或间隙原子的辐照生长、辐照硬化和辐照脆化；研究空间辐射、真空-极低温大温变环境“耦合效应”对焊点影响规律的数值模拟；确立描述各种射线、热、力、复合能场及真空环境作用下焊点界面原子反应、扩散过程机制及规律的基础理论，建立空间环境下焊点损伤评价方法。为研究提高电子器件焊点“抗辐射、抗大温变”能力，探索“无主动热控措施”空间装备的设计和制造技术，满足未来空间装备“减重”、“提高有效载荷比”、“微小型化”的需求提供理论基础。

基于我国“探月工程”、“载人空间站工程”以及未来的航天军用电子产品的制造的潜在需求，本项目以具有代表性的Sn基、Pb基、In基、Au基等钎料合金为研究对象，采用60Co-γ源、液氮和高温环境箱等试验手段，研究了空间辐射、大温变环境以及“辐照+大温变”耦合作用条件下对钎焊焊点元素的迁移及转化、元素的扩散及相变、新相形成条件；研究了焊点界面区组织的辐照损伤，主要包括辐照蠕变、空位或间隙原子的辐照生长、辐照硬化和辐照脆化行为；研究了辐照+大温变“耦合效应”对焊点的影响规律。首次发现了γ射线辐照下焊点辐射缺陷和力学性能的演变规律，建立了γ射线辐照-热循环环境下焊点基体组织的变化及寿命模型；通过大温变热冲击与热循环条件下焊点界面行为和力学性能的对比，首次阐明了焊点界面行为与性能退化的关系及机理；首次发现“环氧树脂复合钎料”可以显著提高钎料焊点的强度（室温强度可以提高50～100%）、显著提高焊点抗辐射能力。焊点在经过-196℃至150℃冷热循环（极低温度大温变热循环）后，力学、电学性能均有显著提高。研究成果将为研究提高电子器件焊点“抗辐射、抗大温变”能力，探索“无主动热控措施”空间装备的设计和制造技术，满足未来空间装备“减重”、“提高有效载荷比”、“微小型化”的需求提供理论基础。