Abstract This paper discusses how Chemical Mechanical Planarization (CMP) is one of the most effective methods in achieving adequate local and global surface planarization and how chemical mechanical polishing of copper attracts a lot of interest. It examines the effects of different factors including the slurry, polishing pads and down force etc. on the quality of planarized copper layer in CMP Cu. It also presents, a new CMP copper technique with the name of ?Abrasive-free polishing (AFP)?.
Outline
Introduction to CMP and CMP Copper(Cu)
Techniques of CMP copper
Removal Mechanism
Slurry-- Chemistry
Slurry?Abrasives Particles
Processing Factors
Polishing Pads
Abrasive-Free Polishing of Copper-a New Technique
Conclusions
From the Paper "Recent years have witnessed the rapid development of using copper (Cu) for low resistivity electrical connections in microelectronic devices.1,2 In fact, copper is one of most commonly used pure metals in the electrical industry because of its low conduct resistivity of about 6?10-8W-m and excellent mechanical properties as well. There are various methods to deposit Cu thin films, for example, electroplating, electroless plating, sputtering and thermal evaporation can be used.3.4 The copper thin films achieved by these techniques, especially those from the electrochemical techniques, are not planar enough to promise a successful multilevel interconnection. However, in fabrication of a logic device with five or more layers, at least one layer should be perfectly planar. Lack of layer planarity may lead to severe problems for photo-lithography (such as insufficient focus depth) and dry etching in sub 0.5 mm 5. Chemical Mechanical Planarization (CMP) is one of the most effective methods in achieving adequate local and global surface planarization.6 Therefore, chemical mechanical polishing of copper attracts a lot of interests in recent years."
