标题: | 锡银焊锡与ENIG /Cu/Ni及OSP /Cu之界面反应研究 Metallurgical Reactions of Sn-2.5Ag Solder with ENIG /Cu/Ni and OSP /Cu Under Bump Metallization |
作者: | 李宜蓁 Li, Yi- Chen 林宏洲 Lin, Hong-Cheu 工学院半导体材料与制程设备学程 |
关键字: | 可靠度;reliability |
公开日期: | 2011 |
摘要: | 随着电子产品愈讲究多功能及轻薄短小,致使电子封装技术也必须与时并进。而在电子封装中,当焊点与基材进行焊接时,焊料会与基材上的金属发生化学反应,进而在界面生成一或多种介金属,而这些介金属对焊点的可靠度影响甚钜。因此,欲提升焊点可靠度,就必须了解焊点与基材间界面反应之情形,且现今在电子封装中最常使用表面处理层为OSP/Cu 与ENIG /Cu/Ni,由于环保意识的抬头与经济的考量 锡球中所使用的焊料也逐渐转为无铅制程。 本研究之主要目的即是探讨无铅锡银与不同的基材表面处理垫层(Surface Finish)之治金反应。实验内容分为三部分:一、焊锡球焊接后,进行高温储存测试,在150℃下,0 - 1000小时之固态时效处理,观察经过不同的时效时间后,其界面之反应与焊点的强度变化。二、进行廻焊测试,顶温是250℃,分别进行0 ~ 10 分钟的廻焊,在廻焊过后观察其反应结果的截面积,并且以扫描式电子显微镜观察界面反应及介金属化合物之生长行为,并利用推球机(Dage Series 4000 Bond Tester)在不同回焊时间下测试其焊点的推力强度。三、试片施以高温储存、高加速压力、压力蒸煮等可靠度的加速试验,藉由推力测试焊锡与不同的基材表面处理层基板间接合强度。 综观可靠度试验后的强度结果:焊锡与OSP及ENIG均有好的焊锡性,两种接点之强度均随时效时间增加而降低。而下降幅度最大为压力蒸煮锅测试,OSP焊锡接点经不同环境条件试验后之接点强度衰减幅度皆大于 ENIG垫层,比较ENIG与OSP焊垫的接着行为,ENIG焊锡接点有较佳抗衰败能力。 With the miniaturization of modern electronic products and devices, the packaging density of components such as chips significantly increases, and the scale of interconnections becomes smaller and smaller. Consequently, the reliability of solder joints plays key roles. And understanding the volume effect of Snag solder on interfacial reaction will be critical in solder joint reliability. The OSP/Cu and ENIG /Cu/Ni surface finish is the most common and important for solder pad and bumps in industry now. In Flip-Chip packaging, lead-free solders are replacing traditional SnPb solders gradually due to environmental concern. The main objective of this proposal is then to study the reactions between such lead-free solders with different surface finish used in the industry. This study divides third parts. First part experiment : After reflow, the solder joints were subjected to thermal aging at 150 oC for time up to 1000 hrs. The bonding strengths of the solder joints with different thermal aging time were then tested. Second part experiment : For the reflow test, the peak reflow temperature was 250℃, and the reflow time was 0-10 minute. The research was to evaluate the reliability of the solder joints by measuring the bonding strength of the solder joints on the FCBGA substrates. Besides, we analyzed the fracture surface and cross-section view. The microstructureal analyses of samples and the composition of reaction product was identified by BEI .The measurements of bonding strength for solder joints were obtained using a Dage Series 4000 Bond Tester. Third part experiment : Reliability test including high temperature storage (HTS), high accelerated stress test (HAST) and pressure cooker test (PCT) were carried out to serve as accelerated tests .Die shear test was applied to study the bonding strength between SnAg solder and different surface finish. From the bonding strength results after reliability tests, the OSP/Cu and ENIG /Cu/Ni surface finish had good solderability. In the other hand, as thermal aging time increased, the bonding strength was decreased. The bonding strength decreased drastically after PCT test. The bonding strength of OSP solder joints is lower than ENIG solder joints. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079675518 http://hdl.handle.net/11536/43995 |
显示于类别: | Thesis |