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

研究了大规模集成电路中铜互连层的低介电常数中间层。热稳定性和分层是该层中的严重问题。在CVD氟碳低ε涂层中，通过控制F含量，可以显著提高涂层的热稳定性。但在低ε层中，与阻挡层的界面结合强度很差。界面反应发生在TaN/FC中间层，Ta扩散到该中间层中。在CVDSIOC中间层中，通过控制碳含量，这些性能得到了显著改善。研究了CMP工艺中Cu和TaN阻挡层的确定。沉积在阻挡层上的Cu层的粘附强度/低ε由阻挡层的性质决定。而沉积在低ε层上的阻挡层的介电常数则取决于中间层的介电常数。当使用低ε层时发生分层。这是低ε过渡层在铜互连线应用中面临的一个严重问题。本文提出了解决这一问题的建议。这种分层可以通过采用较高介电常数的中间层或采用新开发的用于CMP的MnO 2浆料来避免。

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.