A Novel Application of Chemical Mechanical Polishing for Panel Level Organic and Glass Substrate

Chemical mechanical polishing (CMP) is commonly utilized in back-end of IC manufacturing. However, it has never been applied in printed-circuit-board (PCB) industry yet. In this paper, CMP with panel level processing is introduced and some promising results for three different applications are demonstrated. This paper showed the evaluation of smoothing and planning capability for Cu traces of semi-additive process. The variation of copper thickness over the panel size of 510mm × 515mm was improved from as Cu plating of 6.7μm to 3.1μm or even 1.5μm by CMP. Better copper thickness uniformity provides better electrical performance. We also evaluated the smoothing down feasibility of Cu pillars (pads) and obtained the Cu height non-uniformity of <;1.5μm. In the application of CMP in leveling high copper pillar (HCP), the variation of HCP height was reduced from 50μm to 25μm. Finally, CMP was applied to supper fine line on Line Embedded substrate, and the dishing value of the line was about 0.2μm and the line/space of 1.9/2.1μm was achieved.