Process variation is inevitable for any production line regardless of the industry. The trend for smaller, lighter yet multifunctional devices has created high expectation for the semiconductor manufacturer to produce more robust and highly reliable devices. One way to achieve this is by assessing the variance performance of the assembly production. In this study, the mechanical properties of copper alloy C194 used as the lead frame for particular IC device have been investigated. Samples from control and defect groups been subjected to hardness (Rockwell test) and tensile (Instron test) while the optical microscopy used to verify the microstructure. The result shows that the hardness and tensile of the defect group is relatively lower than the control group while the elongation of the defect group is almost 10% higher. This finding is very useful to be shared with the process owner so that in-depth investigation on the lead frame material consistency or the temperature range optimization can be carried out to prevent such variations that contribute to the inconsistence wire bond yield performance.