High-throughput, tip-based in-line nanometrology in semiconductor and nano-featured manufacturing

A high-throughput, tip-based, in-line nanometrology system that can be helpful for developing closed-loop process control in nanomanufacturing of semiconductor industries. One of the most significant barriers stands in the path to in-line inspection in nanomanufacturing is sample-preparation. After the beforehand inspection process detecting regions that have higher chance to be failed, known as “hotspots,” the operator may need to spend much time to position a high-resolution probe to there because small field-of-view (FOV) makes it hard to recognize its position from target. The other barrier to developing in-line inspection is the resolution limitation of conventional metrology technique, a.k.a. optical and e-beam inspections. Especially for technology nodes beyond 10-nm, the critical dimension is going close to resolving capability. As a result, the in-line inspection requires a higher resolution imaging technique with fast and precision method to position the probe. The methodology developed in this study overcomes those barriers by passive alignment methods and a state-of-the-art single-chip atomic force microscopy system. Instead of those prevalent active methods, the passive alignment uses kinematic method providing the wafer adequately constraint to limit degree of freedoms in place. Once the wafer sit into site, a preload applied then a sub-micron precision can be achieved. The passive mechanism almost instantaneously finishes alignment, so no time budget should be counted. Compared with AFM’s FOV, the sub-micron positioning precision guarantees the same location on wafer-by-wafer inspection. To enhance the metrology throughput, the proposed system uses multiple AFM chips distributed over the wafer footprint in order to image on multiple hotspots simultaneously. On the other hand, a flexure-based XY stage which is able to make nm-precision and mm-range is implemented to position AFM probe. The proposed system takes a serial of images neighboring to each other, image-stitching programmatically mosaic all images to generate a large area FOV measurement. This system applies several concepts to thoroughly enhance the throughput of advanced nanometrology and make it compatible with an in-line inspection methodology in the nanomanufacturing process. By the enhanced throughput of metrology, the nanomanufacturing will have a great potential to develop a feedback, process control and improve product’s quality and yield.