Microchip components may involve different polymeric materials for integrated functions, and the thermal bonding of heterogeneous materials is a challenge. This study is devoted to the bonding of polycarbonate (PC) and polymethacrylate (PMMA) materials. For conventional thermal bonding of PC and PMMA, the temperature must be above 150°C. CO 2 is used as a plasticizer to lower the bonding temperature to 90°C. CO 2 also serves as a pressurizing agent to provide uniform bonding pressure. To further improve the bonding strength, surface nano-pillar structures are fabricated on PC before binding it with PMMA. Because of the nano-pillar structures, the contact areas significantly increased, and the structural inter-lock further increased the strength after bonding thereby yielding a bonding strength of 1.20 MPa.
This paper introduces a low-cost, automated wafer alignment system capable of submicron wafer positioning repeatability. Accurate wafer alignment is critical in a number of nanomanufacturing and nanometrology applications where it is necessary to be able to overlay patterns between fabrication steps or measure the same spot on a wafer over and over again throughout the manufacturing process. The system presented in this paper was designed to support high-throughput nanoscale metrology where the goal is to be able to rapidly and consistently measure the same features on all the wafers in a wafer carrier without the need for slow and expensive vision-based alignment systems to find and measure the desired features. The wafer alignment system demonstrated in this paper consists of a three-pin passive wafer alignment stage, a voice coil actuated nesting force applicator, a three degrees-of-freedom (DOFs) wafer handling robot, and a wafer cassette. In this system, the wafer handling robot takes a wafer from the wafer cassette and loads it on to the wafer alignment stage. The voice coil actuator is then used to load the wafer against the three pins in the wafer alignment system and align the wafer to an atomic force microscope (AFM)-based metrology system. This simple system is able to achieve a throughput of 60 wafers/h with a positional alignment repeatability of 283 nm in the x-direction, 530 nm in the y-direction, and 398 nm in the z-direction for a total capital cost of less than $1800.
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