Conference Paper

Full Copper Electrochemical Mechanical Planarization (Ecmp) as a Technology Enabler for the 45 and 32nm Nodes

DOI: 10.1109/IITC.2007.382352 Conference: International Interconnect Technology Conference, IEEE 2007
Source: IEEE Xplore


In this work, we demonstrate the capability of Ecmp to meet the 45 nm and 32 nm technology node requirements in terms of topography behavior, the related electrical spread, lithography DOF budget and ULK compatibility.

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    • "Focusing and leveling have always been playing critical roles in a typical photolithographic system like stepper that operates in projection lithography [1], [2]. Along with the pursuit of higher and higher lithographic resolution, the exposing wavelength decreases while the numerical aperture (NA) increases, which results in a drastic shrink of the depth of focus (DOF) [3]–[5]. To transfer the mask patterns clearly and precisely onto the photoresist, full advantages of the restricted DOF should be taken in focusing and leveling processes. "
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    ABSTRACT: Focusing and leveling are two imperative processes to adjust the wafer onto the ideal focal plane of projection lithography tools. Based on moiré fringes formed by particularly designed dual-grating marks, the four-channel focusing and leveling scheme is proposed and demonstrated. These relationships between the tilted amount of wafer, the vertical defocusing amount, and the phase distributions of moiré fringes are deduced. A single-channel experimental setup is constructed to verify the performances of proposed method. Results indicate that the tilted amount and the vertical defocusing amount can be precisely detected with accuracy at $10^{-4}$ rad and several nanometers level, respectively, and therefore meet the demand of the high-demanding focusing and leveling processes.
    Preview · Article · Aug 2014 · IEEE Photonics Journal
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    ABSTRACT: Electro-chemical mechanical planarization (ECMP) process dissolves copper ions electrochemically by applying an anodic potential on the copper surface in an aqueous electrolyte, and then removes a copper (Cu) complex layer by the mechanical abrasion of a polishing pad or abrasives in the electrolyte. The ECMP process is a low pressure polishing method for metals such as copper, aluminium (Al) and tungsten (W) on dielectric materials such as silicon dioxide, low-k (LK) and ultra low-k (ULK) dielectrics, comparing to the amount of defects by the traditional Cu chemical mechanical planarization (CMP). The polishing pad used in the ECMP process is a conventional closed cell type pad (IC 1400K-groove pad) with holes. It supplies the aqueous electrolyte to the copper surface and removes the copper complex layer. The material removal rate (MRR) and MRR profile were simulated and tested according to the changes of the wafer overhang distance (WOD) from the platen and the electric contact area (ECA). In order to derive the design rule of the system, the experimental results are compared with the simulation results. After the ECMP process, it was verified that the within wafer non-uniformity (WIWNU) was lower than 2% using the relatively uniform ECA pad (C-type) under the smallest WOD condition. The experimental results well matched the simulated results.
    No preview · Article · Nov 2008 · Microelectronic Engineering