Generation of Pad Debris during Oxide CMP Process and Its Role in Scratch Formation

Abstract

The generation of pad debris during the chemical mechanical planarization (CMP) process was studied. A fresh pad was conditioned with deionized water alone without polishing any wafer in order to characterize the pad debris exclusively. It was found that the pad debris presented in several size ranges with irregular shapes, mostly in agglomerated form. Polishing experiments were performed continuously without conditioning the pad, and the byproducts were gathered several times during the process. No pad debris was found in the gathered slurry during this process, but dispersion of some agglomerated silica particles was observed. The slurry was gathered during CMP processes conducted under both in situ and ex situ pad conditions. The generation of pad debris during polishing was observed with in situ conditioning but not observed with ex situ conditioning. The effect of the presence of pad debris on scratch formation was also studied, and it was found that the occurrence of pad debris seriously increased the number of scratches. An increase in the number of diamonds per unit area of a conditioner could ultimately avoid the generation of pad debris, eventually reducing the scratch formation by sustaining the same removal rate and nonuniformity after the CMP process.

Artificial intelligent matching for scratches of semiconductor wafers based on a K-NN algorithm

“…Besides polishing, factors such as contact interface [7], agglomerated particles, pad debris, or hard defects resulting from the wafer bulk also generate kinds of defects on the wafer, in which scratches are a common defect. These aforementioned factors can severely affect the manufacturing process of semiconductor chips [8,9]. Therefore, it is more and more important to automatically locate damaging source based on scratches.…”

Material Removal Behavior of Nano-Sized Cerium Hydroxide Abrasive Slurry for Chemical Mechanical Polishing

“…The sources of microscratch have been intensively investigated and are well known: slurry abrasive, agglomerated slurry abrasive, abraded conditioner diamond, and hard particles from the tools. Besides large and hard particles, recent studies have revealed pad wear debris to be an additional source of scratching on the wafer surface [6][7]. Much literature has addressed the roles of critical particle size and particle properties in scratching mitigation, based on particle-wafer interaction models, and focused on particle size minimization and the dispersion of abrasive particles [8][9][10].…”

CMP Defects; Their Detection and Analysis on Root Causes

“…The possible sources for scratch generation during the CMP process are mainly consumables such as slurry, pad and diamond conditioner. However, the effect of these consumables on scratches has not yet fully studied even though there are few reports [6,7]. The classification is also very different in many publications.…”