Acoustic wave device and method of manufacturing acoustic wave device

A method of manufacturing an acoustic wave device, the method comprising:

• laminating a piezoelectric layer including a first main surface and a second main surface on an opposite side of the first main surface, and a functional electrode provided on at least one of the first main surface and the second main surface of the piezoelectric layer, in a first direction on a first substrate;
• laminating a first insulator and a first land on a first main surface of a second substrate including the first main surface and a second main surface on an opposite side of the first main surface;
• bonding the first substrate and the second substrate such that the first main surface of the piezoelectric layer and the first main surface of the second substrate face each other;
• forming a second insulator on at least a portion of the second main surface of the second substrate;
• forming a through-hole that penetrates the second substrate at a position that overlaps the first land in plan view;
• forming a third insulator on a second main surface of the second substrate, a side wall of the through-hole, and a surface of the first land exposed to the through-hole;
• removing a portion of the third insulator formed in the forming the third insulator;
• and
• forming a through via and a second land in the through-hole and the second main surface of the second substrate after the removing the portion of the third insulator;
• wherein
• in the laminating the first insulator and the first land, the first land is laminated on the first main surface of the second substrate with the first insulator interposed therebetween;
• in the removing the portion of the third insulator, at least a portion of a surface of the first land on a second substrate side at a position that overlaps the through-hole is exposed in plan view;
• and
• in the forming the through via and the second land, at least one second land is formed on the second main surface of the second substrate with the third insulator interposed therebetween.