A novel slurry injector system (SIS – 100) has been developed by Araca Incorporated. The system has been proven to successfully reduce polishing defects and slurry consumption for myriad of chemical mechanical planarization processes.

In most commercial CMP polishers, slurry is applied onto the center of the pad. As the pad rotates during polishing, centrifugal forces cause large amounts of fresh slurry to flow directly off the pad surface without entering the pad-wafer interface. This results in very low slurry utilization. Moreover, as the spent slurry containing polishing by-products and pad debris mixes with the fresh slurry and reenters pad-wafer interface during polishing, it affects removal rate and causes wafer-level defects. Furthermore, as large amounts of ultra pure water (UPW) are used to rinse the pad surface between polishing wafers to remove slurry residue and pad debris off the pad surface, there is an appreciable amount of UPW residing on the pad surface and inside the grooves after rising. This creates a dilution effect during the next wafer polishing and contributes to lower material removal rates.

Different from the above standard pad center area slurry application, the slurry injection system is designed to efficiently introduce fresh slurry into the pad-wafer interface. SIS – 100 is placed on top of the pad during polishing and fresh slurry is applied over the wafer track in a thin film through the SIS – 100. Compared with the standard pad center area slurry application, SIS – 100 has the following advantages due to its intrinsic design:

• Improved slurry utilization by efficient delivery of fresh slurry to the pad-wafer interface.
• Reduced mixing of spent slurry (and residual UPW) with fresh slurry supplied during polishing.
• Higher material removal rate at the same slurry flow rate.
• Equivalent material removal rate at lower slurry flow rates.
• Lower wafer-level polishing defects at the same slurry flow rate.
• Effective capture of foam (due to hydrogen peroxide and surfactants) generated during polishing.

SIS – 100 is totally passive and does not require power or specialized software to be integrated with commercial polishers. Simple retrofit kits are available for most existing and new polishers.

Multiple patents on SIS – 100 have been filed in US, Japan, Korea, Europe, Taiwan and China. Please refer to our Slurry Injector System Brochure for details. Additional information will be furnished to interested parties after the execution of Araca’s standard mutual NDA.