晶圆背面硅腐蚀研究

Research on Silicon Corrosion on the Back of Wafer

随着半导体技术的进步,晶圆的特征尺寸不断缩小,集成度大幅提高。硅晶圆正面制作完成集成电路后,进行背面减薄,使其达到所需要的厚度,可以降低器件热阻、提高工作散热及冷却能力、便于封装,而功率器件芯片,更是需要在晶圆减薄后,进行背面金属沉积,以此作为电极,从而在封装的时候,可以从背面金属上接出引线。硅晶圆在背面研磨减薄后,表面会受到损伤,硅片应力极大,使得翘曲度也极大,容易碎片,因此需要进行背面硅腐蚀,去除损伤层,释放应力。硅腐蚀对背面金属的粘附性存在很大的影响,文章主要研究不同的硅腐蚀液及酸槽条件对背面金属粘附性的影响。

With the progress of semiconductor technology,the feature size of wafer is shrinking and the integration level is greatly improved.After the fabrication of the integrated circuit on the front side of the silicon wafer is completed,Backside Grinding is performed to make it reach the required thickness,which can reduce the thermal resistance of the device,improve the working heat dissipation and cooling capability,and facilitate packaging.For power device chips,it is necessary to perform Backside Metal Deposition as an electrode after the wafer is thinned,so that leads can be connected from the back metal during packaging.After the silicon wafer is ground and thinned on the back surface,the surface will be damaged.The stress of the silicon wafer is extremely high,which makes the warpage extremely high and easy to fragment.Therefore,it is necessary to carry out silicon corrosion on the back surface,remove the damaged layer and release the stress.Silicon corrosion has a great influence on the adhesion of back metal.This paper mainly studies the influence of different silicon corrosion solution and acid bath conditions on the adhesion of back metal.