Abstract: Embossing of metallic glass supercooled liquids into templates is emerging as a precision net-shaping and surface patterning technique for metals. Here, the effect of thickness of metallic glass on template-based embossing is disclosed. The results show that the existing embossing theory developed for thick samples fails to describe the process when the thickness of metallic glass becomes comparable to the template cavity diameter. Increased flow resistance at the cavity entrance results in viscous buckling of supercooled liquid instead of filling. A new phenomenological equation is proposed to describe the thickness dependent filling of template cavities. The buckling phenomenon is analyzed based on the folding model of multilayer viscous media. Controlled buckling can be harnessed in fabrication of metal microtubes, which are desirable for many emerging applications.