Multi-zone Pressure Control for Improvement of Within Wafer Non-uniformity in CMP

Chemical Mechanical Polishing (CMP) is a crucial process in advanced semiconductor manufacturing, essential for achieving global planarization of the wafer surface, which directly impacts device performance and yield. Uniform material removal across the wafer is vital; however, non-uniformity frequently occurs, even with nominally uniform applied pressure. A prevalent issue is the edge effect, where the removal rate at the wafer edge significantly differs from that at the center, resulting in reduced uniformity and compromised device reliability. To tackle this challenge, this study explores the effectiveness of a multi-zone pressure-controlled carrier in enhancing polishing uniformity. Conventional single-zone carriers can only influence a narrow region of approximately 5–7 mm at the wafer edge, leading to limited improvements in nonuniformity of about 3%. In contrast, the multi-zone carrier allows for precise pressure control over a broader range, extending from 3 mm to 20 mm from the wafer edge. Experimental results show that this approach reduces non-uniformity to below 3% while effectively addressing edge removal deficiencies. These findings underscore the significant potential of multi-zone carriers to improve CMP process precision. Consequently, the proposed method is anticipated to enhance both productivity and quality in semiconductor fabrication.