This work aims at understanding and eliminating thermo-mechanically induced circumferential cracks that form during cooling for a 400 °C annealed copper (Cu) through-glass via (TGV) with a mean outer diameter of $47.5~\mu \text{m}$ , made in Corning HPFS fused silica glass. An exponential dependence was found between Cu metallization thickness and the likelihood for the formation of circumferential cracks. For the conditions used in this study, no cracks were formed in the HPFS fused silica substrate for Cu metallization thicknesses $ \mathbf { < } 12 \mu \text{m}$ , however, for thicknesses $ \mathbf {\mathrm {\ge }}~12~\mu \text{m}$ , circumferential crack formation exponentially increased. From finite element analysis (FEA) studies, the corresponding threshold stresses for the initiation of circumferential stresses at $12~\mu \text{m}$ was predicted to be 140 MPa. Therefore, for 400 °C annealed Cu TGV with a mean outer diameter of $47.5~\mu \text{m}$ , made in HPFS fused silica substrate, circumferential stresses can be eliminated when Cu metallization thickness of less than $12~\mu \text{m}$ is used.

中文翻译：

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消除铜穿玻璃通孔基板中热机械驱动圆周裂纹的形成

这项工作旨在了解和消除平均外径为 400 °C 的退火铜 (Cu) 玻璃通孔 (TGV) 在冷却过程中形成的热机械诱导的圆周裂纹。 $47.5~\mu \text{m}$ ，由康宁 HPFS 熔融石英玻璃制成。在 Cu 金属化厚度和形成圆周裂纹的可能性之间发现了指数相关性。对于本研究中使用的条件，HPFS 熔融石英基板中没有形成 Cu 金属化厚度的裂纹 $ \mathbf { < } 12 \mu \text{m}$ ，然而，对于厚度 $ \mathbf {\mathrm {\ge }}~12~\mu \text{m}$ ，周向裂纹的形成呈指数增加。从有限元分析 (FEA) 研究中，相应的起始周向应力的阈值应力在 $12~\mu \text{m}$ 预计为 140 兆帕。因此，对于平均外径为 400 °C 的退火 Cu TGV $47.5~\mu \text{m}$ , 由 HPFS 熔融石英基板制成，当 Cu 金属化厚度小于 $12~\mu \text{m}$ 用来。