MANUFACTURING METHOD OF SILICON DEVICE

PROBLEM TO BE SOLVED: To provide a manufacturing method of a silicon device capable of making it easy to hold a pressure in a cavity portion constant.SOLUTION: A manufacturing method of a pressure sensor 1 includes: a first recess portion forming step of preparing a substrate 50 having a first recess portion 53 and a piezoresistive element 20 disposed on a bottom portion of the first recess portion 53; an AlOfilm forming step of forming an AlOfilm 54 on at least a part of an inner surface of the first recess portion 53 of the substrate 50; a sacrifice layer forming step of forming a sacrifice layer 55 on the first recess portion 53; a lid layer forming step of forming a lid layer 56 having a through-hole 57 overlapping with the first recess portion 53 in a plain view and covering an opening of the first recess portion 53; a sacrifice layer etching step of performing etching from the through-hole 57 to the sacrifice layer 55 by using hydrofluoric acid vapor; and a through-hole sealing step of sealing the through-hole 57.SELECTED DRAWING: Figure 3 【課題】空洞部内の圧力を一定に保持し易くすることが可能な、シリコンデバイスの製造方法の提供。【解決手段】圧力センサー１の製造方法は、第１凹部５３を有し、第１凹部５３の底部にピエゾ抵抗素子２０が配置されている基板５０を準備する第１凹部形成工程と、基板５０の第１凹部５３の内面の少なくとも一部にＡｌ2Ｏ3膜５４を形成するＡｌ2Ｏ3膜形成Ａ工程と、第１凹部５３に犠牲層５５を形成する犠牲層形成工程と、平面視で第１凹部５３と重なる貫通孔５７を有し第１凹部５３の開口を覆う蓋層５６を形成する蓋層形成工程と、沸酸蒸気を用いて貫通孔５７から犠牲層５５をエッチングする犠牲層エッチング工程と、貫通孔５７を封止する貫通孔封止工程と、を含むことを特徴とする。【選択図】図３