Freescale Semiconductor,inc.

Stephen B Springer

Owen R Fay

William H Lytle

Steven Markgraf

A method is disclosed for encapsulating micromechanical elements or features on a substrate. In accordance with the method, a first substrate () is provided which has a patterned surface (). A seed metallization () is then deposited onto the patterned surface, and a structural material layer (), which preferably comprises copper, is electroplated onto the seed metallization. A solder (), such as SnCu, is electroplated onto the metal layer, and the seed metallization, the structural material layer and the solder are removed from the first substrate as a cohesive structure (), through the application of heat or by other suitable means, such that a negative replica of the patterned surface is imparted to the structure. The structure may then be placed on a second substrate () such that the solder is in contact with the second substrate, after which the solder is reflowed. Prior to reflow, the solder may be exposed to a fluorinated plasma, which forms a dry flux on the solder surface in the form of fluorinated metal oxides.

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Mesa, AZ, United States of America

Stephen B Springer