Comparison of Measured and Modeled Lithographic Process Capabilities for 2.5D and 3D Applications Using a Step and Repeat Camera

摘要

Increasing volume using larger substrates with decreasing process margins create new challenges for advanced packaging applications. Key step and repeat camera technology continues being introduced for the mass production of high density interconnects used for 2.5D and 3D technologies that will provide solutions for the challenges encountered. A 2X reduction stepper with unique features achieves the tighter specifications needed for many advanced packaging applications printed on large substrates. A large field-of-view optical projection system utilizes the 350-450nm light spectrum from a mercury arc to expose the circuit patterns from a reticle mask onto a substrate and image features with the optimal fidelity required for advanced packaging technologies. The imaging field prints a large 52mm × 66mm area or 59.4mm × 59.4mm in a single exposure. These features enable a system to process larger substrates in fewer shots which result in higher throughput using lower power. Details of the camera and the adjustments that are provided to extend the range of use for both high power and high fidelity applications are discussed. An extensive evaluation of measured and modeled lithographic capabilities of the step and repeat camera to achieve critical dimensions with precise image placement is provided. Limiting resolution and depth of focus results sampled over the imaging field will be provided and supported with simulation. Results of thin and thick resist patterning will be presented and compared to simulated 3D resist profiles using the MACK4 model.