電鍍法製備銀銅合金薄膜應用於金屬連導線之特性探討

Preparation of Silver-Copper Alloy Film by Electroplating and the Application of the Film on Metallization

張凱民(Kai-Min Chang)

指導教授 ： 方昭訓

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2014年)

https://doi.org/10.6827/NFU.2014.00196

摘要

近年來連導線製程深寬比與電阻值日益重要，隨著製程的進步，真空製程轉向濕式製程的研究大幅增加。近年來有許多研究期望以銀連導線取代銅製程，但使用銀為導線材料仍然有極大穩定性及附著性的問題，本研究利用電鍍法製備沉積AgCu合金薄膜，期望達到較好的電阻率及熱穩定性。
第一部分：探討以銀薄膜在Ru (5 nm及10 nm)/Si基板上作為銀接連導線之特性研究。實驗利用直流(DC)磁控濺鍍法製備Ru (5 nm及10 nm)薄膜在p-type Si(100)基板，在不同的電流(1 mA及5 mA)情況下電鍍Ag薄膜，將試片進行在Ar+H2(5%)氣氛中快速退火10分鐘熱處理溫度300˚C到900˚C，並藉由四點探針(FPP)、表面輪廓移(A-Step)、X光繞射分析儀(XRD)、掃描式電子顯微鏡(SEM)等分析薄膜特性。結果顯示以pH=9之電鍍液在不同電流(1 mA及5 mA)情況下製備沉積Ag/Ru (10 nm)/Si、Ag/Ru (5 nm)/Si薄膜，失效溫度均為600˚C，只有Ag/Ru (10 nm)/Si在電流5 mA情況下失效溫度為700˚C，其最低電阻率為4.0 μΩ-cm。以pH=10電鍍液在不同電流(1 mA及5 mA)情況下製備沉積Ag/Ru (10 nm)/Si、Ag/Ru (5 nm)/Si薄膜，失效溫度分別為600˚C，只有Ag/Ru (5 nm)/Si在電流1 mA情況下失效溫度為500˚C，在Ag/Ru (10 nm)/Si在電流5 mA情況下其退火500˚C最低電阻率為2.4 μΩ-cm。
第二部分：探討加入不同重量硝酸銅電鍍法製備沉積Ag97.3Cu2.7、Ag95Cu5、Ag86.5Cu13.5薄膜在Ru(10 nm)/Si基板上之特性研究。實驗利用直流(DC)磁控濺鍍法製備Ru(10 nm)薄膜在p-type Si(100)基板，以pH=10之電鍍液在電流5 mA情況下電鍍AgCu薄膜，將此些試片在Ar+H2(5%)氣氛中進行快速退火10分鐘熱處理溫度400˚C到800˚C，並藉由四點探針(FPP)、表面輪廓移(A-Step)、X光繞射分析儀(XRD)、掃描式電子顯微鏡(SEM)、化學分析電子光譜儀(ESCA)、穿透式電子顯微鏡(TEM)等分析薄膜特性。結果顯示Ag97.3Cu2.7、Ag95Cu5、Ag86.5Cu13.5失效溫度分別為700˚C、800˚C、800˚C，最低電阻率分別為3.7 μΩ-cm、5.7 μΩ-cm、11.0 μΩ-cm。最後以電鍍法Ag95Cu5合金薄膜沉積之填洞實驗。

關鍵字

銀導線 ； 釕 ； 銀銅合金 ； 擴散阻障層 ； 直流濺鍍 ； 電鍍法

並列摘要

In recent years, high aspect ratio process and low-resistance material are increasing needed for intercomection. A wet process has became increasingly importance. Silver has potential to replace copper as an interconnect material became it has a lowest resistivity (ρ = 1.59 μΩ-cm). Many studies have expected silver to replace copper, but the use of silver as a conductor material still has stability and adhesion issues. This study aims to Ag-Cu alloy films by electroplating so as to achieve the film with low resistivity and better thermal stability.
Part I：To investigate the Ag/Ru/Si as a interconnection. Experiments used a direct current magnetron sputtering to prepare Ru (5 nm or 10 nm) film on a p-type Si (100) substrate. After that, a Ag electroplating under a different current (1 mA and 5 mA) was performed. The films was annealed for 10 minutes via a rapid thermal annealing at Ar + H2 (5%) atmosphere for a temperature ranges from 300˚C to 900˚C. The results showed that Ag/Ru (10 nm) /Si, Ag/Ru (5 nm) /Si films deposited in a solution with pH=9 have a failure temperatures of 600˚C. However, Ag/Ru (10 nm) /Si deposited at 5 mA has a failure temperature of 700˚C. The lowest resistivity of 4.0 μΩ-cm can be obtained. In a solution of pH=10, Ag/Ru (10 nm) /Si and Ag/Ru (5 nm) /Si films have failure temperatures of 600˚C, but Ag/Ru (5 nm) /Si deposited at 1 mA has a failure temperature of 500˚C. The Ag/Ru (10 nm) /Si has the lowest resistivity of 2.4 μΩ-cm.
Part II：Study the properties of electroplated Ag97.3Cu2.7, Ag95Cu5, and Ag86.5Cu13.5 film on Ru (10 nm) /Si. The results showed that failure temperature of Ag97.3Cu2.7, Ag95Cu5, and Ag86.5Cu13.5 was 700˚C, 800˚C, and 800˚C, respectively. The lowest resistivity was 3.7 μΩ-cm, 5.7 μΩ-cm, 11.0 μΩ-cm for Ag97.3Cu2.7, Ag95Cu5, and Ag86.5Cu13.5, respectively. A preliminary study of gap filling of Ag95Cu5 alloy film was also performed.

並列關鍵字

Silver wire ； ruthenium ； AgCu film ； diffusion barrier ； DC sputtering ； Electroplating

參考文獻

[1]M. Quirk and J. Serda, “Semiconductor Manufacturing Technology”, pp. 6, (2000).

[2]J. C. Chiou, H. I. Wang, and M. C. Chen, “Dielectric Degradation of Cu/SiO2/Si Structure during Thermal Annealing”, J. Electrochem. Soc. 143, 990 (1996).

[3]J. C. Chuang and M. C. Chen, “Properties of Thin Ta–N Films Reactively Sputtered on Cu/SiO2/Si Substrates”, Thin Solid Films 322, 213 (1998).

[4]The International Technology Roadmap for Semiconductor, ITRS (2013).

[5]S. Nag et al., “Low temperature pre-metal dielectrics for future ICs”, Solid State Technology, 41, 69 (1998).