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High K MIMCap Dielectric Formed by Anodic Oxidation of Bottom TaN Plate

IP.com Disclosure Number: IPCOM000016712D
Original Publication Date: 2003-Jul-10
Included in the Prior Art Database: 2003-Jul-10
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Abstract

Formation of MIMCap devices by oxidation of TaN by anodization to form a TaON insulator with high dielectric constant

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High K MIMCap Dielectric Formed by Anodic Oxidation of Bottom TaN Plate

  Metal Insulator Metal capacitors (MIMCap) embedded in the multilevel interconnects have been used in mixed signal and radio frequency devices. These MIMCaps are constructed with a bottom metal plate, a dielectric layer, and a top metal plate. Silicon oxide and silicon nitride have so far been used as the dielectric layer. As the requirement for the capacitance of MIMCap increases, the dielectric in between the metal plates needs to be very thin. As an example, the silicon oxide thickness has to be about ~ 35 nm in order to get capacitance at 1fF/m2. Any thickness variation of this thin dielectric increases the electrical leakage between the plates and affects the yield. The process control needed for such a thin dielectric film in thus very stringent. This invention discloses a method of making dielectric materials with high dielectric constant at room temperatures for fabricating MIMCaps. The process involves deposition of TaN on a interleave dielectric (ILD) and subsequently oxidation of the TaN to form Ta2O5(N) with dielectric constant of ~22, as compared to ~4 for silicon oxide, as MIMCap dielectric. The Ta2O5(N) layer is formed by a simple anodic oxidation process of part of the TaN layer.

The process steps are illustrated in the schematic drawings (Fig. 1).

1. A metal interconnecting layer is formed, for example, Cu damascene in silicon oxide.
2. A blanket TaN layer is deposited by reac...