【作者】 曹世成；

【导师】 朱嘉琦；

【作者基本信息】 哈尔滨工业大学 ， 材料学， 2010， 硕士

【摘要】 随着集成电路工艺的发展，铜替代铝成为新一代的互连材料。为了防止铜扩散进硅器件中引起器件性能受损以及提高铜与硅、二氧化硅的粘附性，必须在铜互连线外包裹一层扩散阻挡层。氮化钽具有电阻率低、熔点高、晶格和晶界扩散的激活能高、界面稳定等一系列优异的性能，是当前制备扩散阻挡层的首选材料。因此对氮化钽薄膜的工艺方法、阻挡效果、失效机制等方面的研究对于提高集成电路的互连可靠性起到十分重要的作用。本文采用反应磁控溅射方法在硅衬底上制备氮化钽薄膜、钽薄膜、铜籽晶层，利用掠入射X射线衍射（GIXRD）、原子力显微镜（AFM）、Van derPauw四电极法和表面轮廓仪研究了不同溅射工艺对氮化钽薄膜结构形貌的影响规律以及氮化钽阻挡层在不同温度环境下阻挡性能，并研究了所制备阻挡层的失效机制。通过试验研究，本文得到主要结果如下：本文所制备的氮化钽薄膜均为面心立方结构；晶体结构随工艺参数的改变发生变化，衍射峰峰强随溅射功率和衬底温度的增加而增强，氮气分压的增加使择优取向向（111）晶面偏移；氮化钽薄膜的表面形貌与溅射功率和氮气分压密切相关，与衬底温度的关系不大，其粗糙度随溅射功率的增加而增大，随氮气分压的增加而减小；氮化钽薄膜的方块电阻随溅射功率的增加逐渐减小，随氮气分压的增加逐渐增大，温度对方块电阻的影响不大；溅射功率和衬底温度的增加均会使薄膜的沉积速率增加，而氮气分压增加时，沉积速率不升反降；对Cu/barrier/Si互联体系真空热处理，钽阻挡层在600℃时失效，Ta-Si界面发生反应形成TaSi2，此温度下氮化钽阻挡层衍射峰的强度有所增强但没有新相产生，依然具有良好的扩散阻挡特性。通过选取适当的工艺参数，本文成功制备出具有高温阻挡性能的氮化钽薄膜，且所制备的氮化钽薄膜具有良好的表面形貌和电学性能，满足其作为扩散阻挡层的性能要求。更多还原

【Abstract】 With the development of integrated circuits (ICs), metal copper has been areplacement for metal aluminum in high density IC manufacture. But Cu is quitemobile in Si and has poor adhesion to Si or SiO2, which could degrade theperformance of copper interconnect. Therefore, a diffusion barrier layer betweencopper interconnect and Si device is necessary.Tantalum nitride has a series of outstanding properties, such as low resistivity,high melting point, high activation energy of lattice and grain boundary diffusion,and excellent chemical stability, stable interface, which is the optimal choice ofdiffusion barrier materials. So it is very important for the reliability of copperinterconnect to conduct research on the deposition technology, the stability ofbarrier layer and the failure mechanism.In this paper, Tantalum nitride films, Tantalum films, Cu seed layers have beenprepared by reactive magnetron sputtering on Si substrates, and their structure andelectrical properties have been characterized using grazing incidence X-raydiffraction (GIXRD), atomic force microscopy (AFM), Van der Pauw four-probemethod and surface profilometer. The effect of deposition process on structure andsurface morphology of Tantalum nitride films, the diffusion barrier property indifferent high temperature conditions as well as failure mechanism of Cu/barrier/Sifilms were studied.The work can be summarized as follows:The crystal structure of TaN films which were prepared in this paper is f.c.c.and the crystal structure changed with the different processing parameters. theintensity of diffraction peaks became higher when sputtering power and substratetemperature increased, and (111) orientation became dominant with the nitrogenpartial pressure increased; The surface morphology of Tantalum nitride films had aclose relationship with sputtering power and partial pressure of nitrogen, which it isalmost no influenced by the substrate temperature. From the date, we found that theroughness of films increased with an increase of sputtering power and reduces ofnitrogen differential pressure; TaN films’sheet resistance reduced with an increaseof sputtering power ,but sheet resistance increased when partial pressure of nitrogenincrease, at the same time, temperature had little effect on the sheet resistance; The deposition rate decreased with an increase of nitrogen partial pressure whileincreased with increases of sputtering power and substrate temperature. Thenvacuum thermal annealing was performed on Cu/barrier/Si interconnection systems.At 600℃, Ta barrier failed because the formation of TaSi2 that resulted frominterface reaction at Ta/Si. But under the same temperature, there was no phaseformed in TaN barriers while the intensity of diffraction peaks became higher, andthe diffusion barrier property of TaN films still good.TaN films with good diffusion barrier property in high temperature weresuccessfully prepared by reactive magnetron sputtering and meet the requirementsof surface morphology, electrical property for diffusion barrier layer.更多还原