Synergetic effect of chelating agent and nonionic surfactant for benzotriazoleremoval on post Cu-CMP cleaning

The cleaning of copper interconnects after chemical mechanical planarization (CMP) process is a critical step in integrated circuits (ICs) fabrication. Benzotriazole (BTA), which is used as corrosion inhibitor in the copper CMP slurry, is the primary source for the formation of organic contaminants. The presence of BTA can degrade the electrical properties and reliability of ICs which needs to be removed by using an effective cleaning solution. In this paper, an alkaline cleaning solution was proposed. The alkaline cleaning solution studied in this work consists of a chelating agent and a nonionic surfactant. The removal of BTA was characterized by contact angle measurements and potentiodynamic polarization studies. The cleaning properties of the proposed cleaning solution on a 300 mm copper patterned wafer were also quantified, total defect counts after cleaning was studied, scanning electron microscopy (SEM) review was used to identify types of BTA to confirm the ability of cleaning solution for BTA removal. All the results reveal that the chelating agent can effectively remove the BTA residual, nonionic surfactant can further improve the performance.     

An 8-18 GHz broadband high power amplifier

An 8-18 GHz broadband high power amplifier(HPA) with a hybrid integrated circuit(HIC) is designed and fabricated.This HPA is achieved with the use of a 4-fingered micro-strip Lange coupler in a GaAs MMIC process.In order to decrease electromagnetic interference,a multilayer AlN material with good heat dissipation is adopted as the carrier of the power amplifier.When the input power is 25 dBm,the saturated power of the continuous wave(CW) outputted by the power amplifier is more than 39 dBm within the frequency range of 8-13 GHz,while it is more than 38.6 dBm within other frequency ranges.We obtain the peak power output,39.4 dBm,at the frequency of 11.9 GHz.In the whole frequency band,the power-added efficiency is more than 18%.When the input power is 18 dBm,the small signal gain is 15.7±0.7 dB.The dimensions of the HPA are 25×15×1.5 mm~3.     

CMP工艺参数对TiO_2薄膜去除速率的影响

在TiO2薄膜化学机械抛光(CMP)加工过程中,TiO2薄膜的材料去除速率(MRR)非常重要。对抛光工艺参数进行了优化研究,CMP实验采用自主配制的碱性抛光液对TiO2进行抛光,研究了抛光压力、抛光液流量、抛光头转速和抛光盘转速对材料去除速率的影响。实验结果表明:在抛光压力为1 psi(1 psi=6 895 Pa)、抛光液流量为250 mL/min、抛光头转速为87 r/min、抛光盘转速为80 r/min的工艺条件下,TiO2薄膜去除速率达到61.2 nm/min,既节约了成本又保证了较高的材料去除速率。     

一个8~18GHz的宽带高功率放大器

设计研制了一个8~18GHz的混合集成电路宽带高功率放大器。高功率放大器由基于GaAs MMIC工艺的4指微带兰格耦合器实现。为了减小电磁干扰,采用散热效果好的多层AlN材料作为功率放大器的载体。当输入功率为25dBm时,功率放大器输出连续波饱和功率在8–13 GHz 频率范围内大于39dBm,在其他频率范围内大于38.6dBm,在11.9GHz我们得到最大输出功率39.4dBm。在整个频带内,功率附加效率大于18%,当输入功率为18dBm时小信号增益为15.70.7 dB。高功率功率放大器尺寸为25mm*15mm*1.5mm.     

28nm集成电路铜互连弱碱性阻挡层抛光液性能北大核心

报道了一种用于技术节点为28 nm的集成电路多层铜互连阻挡层化学机械平坦化(CMP)的弱碱性抛光液(pH值为8.5),仅由平均粒径为20 nm的硅溶胶、FA/O多羟多胺螯合剂及非离子表面活性剂组成。实验结果表明,研发的弱碱性阻挡层抛光液对牺牲层SiO2、阻挡层Ta及金属互连线Cu等多种材料具有优异的速率选择性,去除速率一致性大于95%,并在28 nm多层铜布线片阻挡层CMP后具有较高的平坦化性能,分别获得了20 nm以下深度的碟形坑和蚀坑。通过电化学极化曲线测试表明,此弱碱性阻挡层抛光液能有效减少Cu和Ta之间的腐蚀电位差,并避免了铜互连结构Cu和Ta界面处电偶腐蚀的产生,这对提高集成电路芯片可靠性具有重要意义。