Process development for a very precise placement of a lens for micro-optics based components

This paper describes the development of a process for placing a lens very precisely in front of a laser source, using a UV resin. The problem of placing accurately each other some optical components is crucial in micro-optics based components. A good alignment is necessary to guarantee the desired performances. Our approach combines the optical simulation and design with the experimental knowledge of the process to achieve a repeatable and cost effective alignment of a lens in front of a laser source. The lens is actively aligned and is fixed to the substrate by UV resin. Some optical simulations have been performed to calculate the right working distance of the lens and to evaluate the target beam shape. Also the substrates have been designed in order to minimize the pre alignment tolerances. We developed an experimental set up for monitoring the beam shape in real time and for precise alignment and attachment of the lens. The monitor is operating also during UV irradiation process. An optimization of all the process parameters has been carried out. The beam peak and beam centroid have been measured before and after the attachment. The post curing shift has been evaluated by the optical simulator and with analytical method. The final post curing shift is around 1 micron, which is compliant with the most stringent requirements in micro optics packaging.