Arul Chakkaravarthi Arjunan

Microlens Array Fabrication by Chemical Mechanical Polishing

Chemical mechanical polishing (CMP) was used to shape hexagonally arranged 20 μm diam cone-shaped structures, prepared by wet etching of Coming 2496 glass, into microlenses. Edge rounding, which occurs during CMP due to a higher removal rate at the edges, was utilized for shaping of the microlenses. Microlenses with an H/D ratio of ∼ 1/10 and radius of curvature of 27.5 μm were obtained. CMP variables that affect the contact pressure and material removal rate are downpressure, linear velocity, slurry, and properties of the pad. These variables being external to substrate provide great flexibility and, hence, suitability of the process for a wide range of materials.

Micro-architecture embedding ultra-thin interlayer to bond diamond and silicon via direct fusion

The continuous demand on miniaturized electronic circuits bearing high power density illuminates the need to modify the silicon-on-insulator-based chip architecture. This is because of the low thermal conductivity of the few hundred nanometer-thick insulator present between the silicon substrate and active layers. The thick insulator is notorious for releasing the heat generated from the active layers during the operation of devices, leading to degradation in their performance and thus reducing their lifetime. To avoid the heat accumulation, we propose a method to fabricate the silicon-on-diamond (SOD) microstructure featured by an exceptionally thin silicon oxycarbide interlayer (∼3u2009nm). While exploiting the diamond as an insulator, we employ spark plasma sintering to render the silicon directly fused to the diamond. Notably, this process can manufacture the SOD microarchitecture via a simple/rapid way and incorporates the ultra-thin interlayer for minute thermal resistance. The method invented herein expects to minimize the thermal interfacial resistance of the devices and is thus deemed as a breakthrough appealing to the current chip industry.