Mechanical testing of gold membranes on a MEMS device for drug delivery

A MEMS device for drug delivery has been developed to achieve controlled release of drugs on demand. It consists of a silicon substrate into which micro-reservoirs are etched that contain individual doses of drug. The release of drugs is achieved by the electrochemical dissolution of the gold membranes that seal individual reservoirs. It is desirable to non-destructively evaluate the mechanical properties of gold membranes on this drug delivery device and to understand the effect of various processing and loading factors on the membrane disintegration process. This study presents some initial bulge test results on gold membranes of this device. The bulge test was conducted by applying pressure to the reservoirs and measuring the deflection of the membrane using interferometry. The test also provides a reliable non-destructive method to evaluate the bottom nitride etching step in the microfabrication process, which is otherwise difficult to test using conventional methods. There is a decreasing trend in the burst pressure with longer corrosion time to the gold membrane. These results will guide us to optimize the design of gold membrane structure through microfabrication process to achieve more reliable device performance.