激光转移铜锡单IMC薄膜工艺及与铜锡薄膜界面行为

发布时间：2018-02-27 04:13

  本文关键词： IMC薄膜 激光前向转移 Cu3Sn 单IMC焊点 界面行为　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着微电子技术的进步,电子产品向着更小、更快、更薄方向发展,使微互连焊点的尺寸减小,焊点内金属间化合物(Intermetallic Compound,IMC)所占体积比增大,焊点向着微纳尺度进一步发展将促使全部由IMC构成的焊点出现,由单种IMC构成的焊点相比传统焊点有其独特优良的性能,因此,对快速制备组织可控的单IMC焊点进行工艺探索和研究具有重要意义。本文首先对电沉积锡进行参数优化,并对电沉积制备多层铜锡薄膜进行工艺研究,随后完成石英基板上单IMC薄膜(Cu3Sn)的制备。利用激光前向转移技术(Laser-Induced Forward Transfer)将石英基板上的IMC薄膜转移到接收基板上,实现LIFT转移IMC薄膜的参数(功率、离焦值)优化,对LIFT转移机理进行分析,并对激光辐照薄膜温度场分布进行了模拟。利用LIFT技术将IMC薄膜转移到铜基体或Cu/Sn薄膜上,制备Cu/Cu3Sn/Sn或Cu3Sn/Sn/Cu结构,高温存储反应后研究其界面行为,为利用LIFT技术快速诱发制备单IMC焊点提供技术依据。研究结果表明:分别通过磁控溅射、电沉积在石英基板上制备Cu层和Sn层后,300℃保温0.25h可完成单Cu3Sn薄膜的制备,适当增加保温时间可减小薄膜因内应力从基板上剥落的倾向。利用电沉积方法制备多层Cu/Sn薄膜时,因铜锡置换反应而使多层薄膜缺陷较多,厚度难以控制。经实验证明激光的单脉冲功率、聚焦点位置、基板间距、脉宽都是影响LIFT转移IMC薄膜的重要因素,高斯激光能量分布不均匀,LIFT转移IMC薄膜易得到“火山口”形沉积点,增大激光功率,沉积点“火山口”形趋势越明显,增大离焦值可以使高斯激光能量分布更均匀,沉积点厚度分布更均匀,通过控制单脉冲功率和离焦值可获得厚度分布均匀的沉积点。沉积点尺寸随单脉冲功率增加而增加,随离焦值增加先增加后下降,LIFT过程中,长脉冲激光转移存在热扩散,IMC薄膜主要以熔化态及固态形式进行转移。EDS和XRD结果证明薄膜转移前后成分没有明显变化。数值模拟结果显示,激光功率越大,作用时间越长,在束缚界面处的温度场分布越不均匀,径向梯度越大(特别是中心区域),激光通过散焦可以让束缚界面温度场分布更均匀,与实验结果完全相符。Cu/Cu3Sn/Sn结构保温反应后形成单IMC层,部分区域存在氧化层,氧化层与Cu3Sn层结合较好。Cu3Sn/Sn/Cu结构在保温反应后形成单IMC层,未施压条件下转移IMC层与新生成的IMC层部分区域发生了较好结合。
[Abstract]:With the progress of microelectronics technology, electronic products are developing in the direction of smaller, faster and thinner, which reduces the size of microinterconnection solder joint and increases the volume ratio of intermetallic compound intermetallic component IMCin solder joint. The further development of solder joints towards micro and nano scale will promote the appearance of solder joints composed of all IMC. The solder joints composed of single IMC have unique and excellent properties compared with traditional solder joints. It is of great significance to explore and study the rapid preparation of single IMC solder joints with controllable microstructure. In this paper, the parameters of electrodeposition of tin are optimized, and the process of preparing multilayer copper-tin thin films by electrodeposition is studied. Then the preparation of single IMC thin film Cu3Snon quartz substrate was completed. Laser-Induced Forward transfer technique was used to transfer the IMC film on quartz substrate to the receiving substrate, and the parameters (power, defocus value) of LIFT transfer IMC film were optimized. The mechanism of LIFT transfer was analyzed, and the temperature field distribution of laser irradiated films was simulated. IMC films were transferred to copper or Cu/Sn films by LIFT technique to prepare Cu/Cu3Sn/Sn or Cu3Sn/Sn/Cu structures. The interface behavior was studied after high temperature storage reaction. The results show that Cu layer and Sn layer can be deposited on quartz substrate by magnetron sputtering and deposited on quartz substrate at 300 鈩，

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