Bottom Coverage of Cu Deposit for 200-nm-Class Circular Vias with High Aspect Ratios Investigated by Magnetron Sputtering Activated Using Superconducting Bulk Magnet
Bottom Coverage of Cu Deposit for 200-nm-Class Circular Vias with High Aspect Ratios Investigated by Magnetron Sputtering Activated Using Superconducting Bulk Magnet
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DOI：
10.1143/jjap.43.6026
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发表时间：
2004-09
影响因子：
1.5
通讯作者：
H. Hazama;T. Matsuda;U. Mizutani;H. Ikuta;Y. Yanagi;Y. Itoh;Kazuo Sakurai;A. Sekiguchi;A. Imai
中科院分区：
文献类型：
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作者：
H. Hazama;T. Matsuda;U. Mizutani;H. Ikuta;Y. Yanagi;Y. Itoh;Kazuo Sakurai;A. Sekiguchi;A. Imai
我们用配备超导块状磁体的磁控溅射装置沉积铜，研究了不同长宽比的圆形通孔在硅衬底上的底部复盖效应。将直径为60 mm的SmBa2Cu3O7-δ超导块材在52K下磁化至4.5T，然后在制冷机中冷却至40K。它作为一种永磁体，产生的磁场强度约为传统Nd-Fe-B永磁体的10倍，从而显著提高了铜靶上的等离子体密度。当使用直径为150 mm的铜靶时，目前的磁控溅射装置能够在至少3.33×10-3PaAr气压下进行溅射，抛射距离DST为300 mm。当DST扩展到500 mm时，在2.66×10-2Pa下仍可实现实际溅射。在此条件下，在直径为120 mm、直径为250 nm、深度为1.15µm、长宽比为4.6的圆形通孔底部成功沉积了底部覆盖率为58%的均匀铜膜。
We have investigated the bottom coverage effect of circular vias with different aspect ratios patterned on Si substrates by depositing Cu using a magnetron sputtering apparatus equipped with a superconducting bulk magnet. The superconducting SmBa2Cu3O7-δ bulk of 60 mm diameter was magnetized up to 4.5 T at 52 K and cooled to 40 K in a refrigerator. It served as a permanent magnet producing magnetic fields about 10 times as strong as that obtained from a conventional Nd–Fe–B permanent magnet, resulting in a marked enhancement in plasma density on the Cu target. Indeed, the present magnetron sputtering apparatus was capable of sputtering under Ar gas pressures of at least 3.33 ×10-3 Pa with a throw distance Dst of 300 mm when a Cu target of 150 mm diameter was employed. Practical sputtering was possible under 2.66 ×10-2 Pa even when Dst was extended to 500 mm. Under this condition, a uniform Cu film with a bottom coverage of 58% was successfully deposited at the bottom of a circular via of 250 nm diameter and 1.15 µm depth with an aspect ratio of 4.6 within a circle of 120 mm diameter on the substrate.