GLSI多层铜互连阻挡层CMP中铜沟槽剩余厚度的控制
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摘要
GLSI铜布线阻挡层化学机械抛光(CMP)中铜沟槽剩余厚度(H_(Cu))关系着集成电路的电性能,是集成电路制造工艺重要评定参数之一。使用不同配比的新型弱碱性抛光液对多层铜布线的阻挡层进行CMP,研究了抛光液中不同体积分数的螯合剂FA/OⅡ、氧化剂H_2O_2和抑菌剂BIT条件下对H_(Cu)的影响。结果表明,随着FA/OⅡ体积分数的增加,铜的去除速率(v_(Cu))逐渐变大,当其体积分数增至3. 5%后,vCu呈略微下降态;加入H_2O_2可使v_(Cu)先迅速地增加,在其体积分数增至1. 5%后vCu开始下降。FA/OⅡ型螯合剂、H_2O_2在低体积分数时对铜均有强去除作用; BIT对铜的抑制作用较大,其体积分数的增加使得v_(Cu)不断减小。三者的协同作用实现了对H_(Cu)的有效控制。
The residual copper thickness in the trench( H_(Cu)) of GLSI copper wiring barrier layer after chemical mechanical polishing( CMP) process is related to the electrical performances of the integrated circuit,and which is one of the most important evaluation parameters of the integrated circuit manufacturing process. A new weakly alkaline slurry with different proportions was used in the CMP process of the multilayer copper wire barrier layer. The effects of different volume fractions of chelating agent FA/O Ⅱ,oxidant H_2O_2 and bacteriostatic agent BIT on the H_(Cu) were investigated. The results show that with the increase of FA/O Ⅱ volume fraction,the removal rate of copper( v_(Cu)) is gradually increased until the FA/O Ⅱ volume fraction reaches to 3. 5%,then v_(Cu)decreases slightly. Similarly,v_(Cu) increases rapidly with the addition of H_2O_2 and then decreases after the volume fraction of H_2O_2 reaches to 1. 5%. Chelating agent FA/O Ⅱ and H_2O_2 have strong effects on copper removal at a low volume fraction; BIT has a visible inhibitory effect on copper,v_(Cu) constantly declines with the increase of BIT volume fraction. The effectively control of H_(Cu)is achieved by the synergy of the three components of slurry.
The residual copper thickness in the trench( H_(Cu)) of GLSI copper wiring barrier layer after chemical mechanical polishing( CMP) process is related to the electrical performances of the integrated circuit,and which is one of the most important evaluation parameters of the integrated circuit manufacturing process. A new weakly alkaline slurry with different proportions was used in the CMP process of the multilayer copper wire barrier layer. The effects of different volume fractions of chelating agent FA/O Ⅱ,oxidant H_2O_2 and bacteriostatic agent BIT on the H_(Cu) were investigated. The results show that with the increase of FA/O Ⅱ volume fraction,the removal rate of copper( v_(Cu)) is gradually increased until the FA/O Ⅱ volume fraction reaches to 3. 5%,then v_(Cu)decreases slightly. Similarly,v_(Cu) increases rapidly with the addition of H_2O_2 and then decreases after the volume fraction of H_2O_2 reaches to 1. 5%. Chelating agent FA/O Ⅱ and H_2O_2 have strong effects on copper removal at a low volume fraction; BIT has a visible inhibitory effect on copper,v_(Cu) constantly declines with the increase of BIT volume fraction. The effectively control of H_(Cu)is achieved by the synergy of the three components of slurry.
引文
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[13] CHENG J. Galvanic corrosion inhibitors for Cu/Ru couple during chemical mechanical polishing of Ru[J].2018,6(1):62-67.
[14] JIANG L,HE Y,NIU X,et al. Synergetic effect of benzotriazole and non-ionic surfactant on copperchemical mechanical polishing in KIO4-based slurries[J]. Thin Solid Films,2014,558(17):272-278.
[15] FRIEDRICH M,GLVEZ-RUIZ J C,KLAPTKE T M,et al. BTA copper complexes[J]. Inorganic Chemistry,2005,44(22):8044-8052.
[2]岳昕,刘玉岭,王辰伟,等.阻挡层抛光中布线槽铜电阻Rs的控制机制研究[J].稀有金属,2018(4):386-392.YUE X,LIU Y L,WANG C W,et al. Mechanism of wiring groove copper resistance control for barrier layer polishing[J]. Chinese Journal of Rare Metals,2018(4):386-392(in Chinese).
[3]蒋勐婷.低压低磨料浓度碱性铜抛光液平坦化性能的研究[D].天津:河北工业大学,2015.
[4] KRISHNAN M,NALASKOWSKI J W,COOK L M.Chemical mechanical planarization:slurry chemistry,materials,and mechanisms[J]. Chemical Reviews,2010,110(1):178.
[5] HONG J,NIU X,LIU Y,et al. Removal rate and surface quality of the GLSI silicon substrate during the CMP process[J]. Microelectronic Engineering,2017,168:30-34.
[6] GAO J,LIU Y,WANG C,et al. Mechanism analysis of the affect the copper line surface roughness after FA/O alkaline barrier CMP[J]. Journal of Semiconductors,2014,35(12):154-158.
[7]李秀娟,金洙吉,苏建修,等.铜化学机械抛光中的平坦性问题研究[J].半导体技术,2004,29(7):30-34.LI X J,JIN Z J,SU J X,et al. Research on the planarity in the copper chemical mecha-nical polishing process[J]. Semiconductor Technology, 2004, 29(7):30-34(in Chinese).
[8] HONG J,NIU X,LIU Y,et al. Effect of a novel chelating agent on defect removal during post-CMP cleaning[J].Applied Surface Science,2016,378:239-244.
[9] PRASAD Y N,RAMANATHAN S. Chemical mechanical planarization of copper in alkaline slurry with uric acid as inhibitor[J]. Electrochimica Acta,2007,52(22):6353-6358.
[10] MANIKONDA S L,ZHANG D,GIRIDHARAN R R,et al.Methodology to estimate TSV film thickness using a novel inline“adaptive pattern registration”method[C]∥Proceedings of IEEE Advanced Semiconductor Manufacturing Conference. Saratoga Springs,NY,USA,2015:78-83.
[11] LI J,LIU Y,WANG T,et al. Electrochemical investigation of copper passivation kinetics and its application to low-pressure CMP modeling[J]. Applied Surface Science,2013,265(1):764-770.
[12] LUAN X D,LIU Y L,WANG C W,et al. A study on exploring the alkaline copper CMP slurry without inhibitors to achieve high planarization efficiency[J]. Microelectronic Engineering,2016,160(C):5-11.
[13] CHENG J. Galvanic corrosion inhibitors for Cu/Ru couple during chemical mechanical polishing of Ru[J].2018,6(1):62-67.
[14] JIANG L,HE Y,NIU X,et al. Synergetic effect of benzotriazole and non-ionic surfactant on copperchemical mechanical polishing in KIO4-based slurries[J]. Thin Solid Films,2014,558(17):272-278.
[15] FRIEDRICH M,GLVEZ-RUIZ J C,KLAPTKE T M,et al. BTA copper complexes[J]. Inorganic Chemistry,2005,44(22):8044-8052.