COPPER WIRING AND MANUFACTURING METHOD OF THE SAME

• Main Authors: TAMAHASHI KUNIHIRO, ITO MASAHIKO, SHINOJIMA YASUSHI, INAMI TAKASHI, ONUKI HITOSHI
• Format: Patent
• Language: English; Japanese
• Published: 13.09.2018
• Subjects: APPARATUS THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMISTRY; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; METALLURGY; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; SEMICONDUCTOR DEVICES

PROBLEM TO BE SOLVED: To obtain a low resistance and fine copper wiring.SOLUTION: It is confirmed that a crystal grain is coarsened more as a coating ratio becomes lower due to an impurity. Especially, when the coating ratio is 25% (c), a mean particle diameter is large similarly to the case where the coating ratio is 0 (d), and is greatly improved than the case where the coating ratio is 50% (b). As mentioned above, when using a plating liquid of 6 N and 9 N, an impurity as a problem in here is mainly a compound of Cl and O, and concentration of Fe is low. Thus, the coating ratio is corresponded to a ratio to be covered with an atom of such impurity by the atom constructing a surface of the crystal grain, As mentioned above, when the concentration of the plating liquid is 9 N as example, the concentration of an addition agent is adjusted, and a thermal processing is performed before the mean particle diameter of a copper layer before a thermal processing step is set at 28nm or less, a specific resistance of the copper layer can be reduced to less than 4μΩ cm of the conventional one even when the coating ratio is 25% as mentioned above.SELECTED DRAWING: Figure 15 【課題】低抵抗かつ微細な銅配線を得る。【解決手段】この不純物による被覆率が小さくなるに従って結晶粒が粗大化していることが確認できる。特に、この被覆率が２５％の場合（ｃ）には、被覆率が０の場合（ｄ）と同等に平均粒径が大きく、かつ５０％の場合（ｂ）よりも大幅に大きく向上している。また、前記の通り、６Ｎ、９Ｎのめっき液を用いた場合には、ここで問題となる不純物は主にＣｌとＯの化合物であり、Ｆｅの濃度は低い。このため、上記の被覆率は、結晶粒の表面を構成する原子がこのような不純物の原子で覆われた割合に対応する。上記のように、例えばめっき液の濃度を９Ｎとし、かつ添加剤の濃度を調整して熱処理工程前における銅層の平均粒径を２８ｎｍ以下と小さくしてから熱処理を行うことにより、上記のようにこの被覆率が２５％とした場合でも、銅層の比抵抗を従来の４μΩ・ｃｍよりも低下させることができる。【選択図】図１５