CMP defect reduction by micro-scratch control using new monitoring technique

One of the challenges in CMP process is the continuous reduction of micro-scratches induced by the polishing. A series of studies was performed to look for a solution to reduce it and to prevent impact on the product wafer. Implementation of buffing on soft pad and POU filter can help to reduce CMP micro-scratches. Adding a good monitoring scheme using the offline defectivity tool KT SP1 helps to prevent impact on a product wafer. From the data, offline monitoring gave a very good indication on what will happen to the product wafer. By using offline monitoring to qualify the tool before the next production run will serve as protection for the lot quality and thus lead to yield improvement.