Thermally stable low dielectric constant interlayers for high speed MOS LSI's

研究了用于大规模集成电路的低介电常数铜互连层。热稳定性和脱层是该层的主要问题。在CVD低ε氟碳层中，通过控制F含量可以明显改善其热稳定性。然而，在低ε层中，与势垒层的界面处附着强度很差。界面反应发生在TaN/FC层上，Ta深入扩散到该层中。在CVD SIOC夹层中，通过控制碳含量，这些性能得到了显著改善。研究了CMP法测定铜和钽阻挡层的方法。沉积在阻挡层/低ε上的Cu层的粘附强度取决于阻挡层的性质。而沉积在低ε层上的势垒层的介电常数则与层间介电常数有关。当使用低ε层时，会发生脱层现象。这是低ε间层在铜互连中的应用所面临的一个严重问题。本文提出了解决这一问题的建议。采用较高介电常数的中间层或采用新开发的二氧化锰浆料可避免这种脱层现象。

Low dielectric constant intertayer for Cu interconnection layer employing in LSI is studied. Thermal stability and delamination are serious problem in this layer. In CVD fluorocarbon low ε layer, thermal stability can be improved markedly with the control of F content. However, adhesion strength is very poor at the interface with barrier layer in low ε layer. Interfacial reaction occurs at the TaN/FC intertayer and Ta diffuses deeply into this interlayer. In CVD SIOC interlayer, these properties were improved markedly with controlling of the carbon content. Determination of Cu and TaN barrier layers are studied in the CMP process. Adhesion strength of Cu layer deposited on the barrier layer/low ε is determined by the properties of barrier layer. However, that of barrier layer deposited on low ε layer is by the dielectric constant of interlayer. DelaminaUon occurs when low ε layer is used. This is serious problem in the application of low ε interlayer to the Cu interconnection. This paper gives proposal to solve this problem. This delaminalion can be avoided with employing higher dielectric constant interlayer or with employing of newly developed MnO2 slurry for the CMP.