Acoustic wave device and method of manufacturing acoustic wave device

An acoustic wave device comprising:

• a piezoelectric layer including a first principal surface and a second principal surface that face in opposite directions;
• at least one pair of electrodes located on the first principal surface and opposing each other in an intersecting direction intersecting a thickness direction extending perpendicularly or substantially perpendicularly to the first principal surface;
• a support substrate located on the second principal surface and including a first cavity extending through the support substrate so as to overlap at least a portion of the at least one pair of electrodes as viewed in the thickness direction;
• a first cover located on a surface of the support substrate opposite to the piezoelectric layer to close the first cavity;
• wiring electrodes located on the first principal surface and electrically connected to respective electrodes of the at least one pair of electrodes;
• a support frame including a second cavity and surrounding the at least one pair of electrodes;
• and
• a second cover located on a surface of the support frame opposite to the piezoelectric layer to close the second cavity;
• wherein
• the first cover and the second cover are made of a resin sheet including a photosensitive resin.

A method of manufacturing acoustic wave devices, the method comprising:

• an aggregation body preparing step of preparing an aggregation body of acoustic wave devices in which multiple acoustic wave devices are integrated into one body;
• and
• a separation step of separating the aggregation body into individual acoustic wave devices after the aggregation body preparing step;
• wherein
• the aggregation body preparing step includes:
• an intermediate product preparing step of preparing an intermediate product including a piezoelectric layer including a first principal surface and a second principal surface that face in the opposite directions and also including multiple divided regions on the first principal surface, the first principal surface being divided into the divided regions as viewed in a thickness direction extending perpendicularly or substantially perpendicularly to the first principal surface, at least one pair of electrodes formed on the first principal surface in each one of the divided regions and opposing each other in an intersecting direction intersecting the thickness direction, wiring electrodes formed on the first principal surface in each one of the divided regions and electrically connected to respective ones of the at least one pair of electrodes, and a support substrate formed on the second principal surface so as to extend across borders of the divided regions;
• a support frame forming step of forming multiple support frames including respective second cavities after the intermediate product preparing step;
• a second cover forming step of providing a second cover on the multiple support frames so as to close the respective second cavities after the support frame forming step;
• a first cavity forming step of forming first cavities through the support substrate in respective divided regions after the second cover forming step;
• a first cover forming step of forming a first cover on the support substrate so as to close the first cavities after the first cavity forming step;
• a terminal hole forming step of forming terminal holes through each of the support frames and the second cover or through the support substrate and the first cover after the second cover forming step;
• an under-bump metal forming step of forming under-bump metal bodies in respective terminal holes after the terminal hole forming step;
• and
• a bump forming step of forming bumps on respective under-bump metal bodies after the under-bump metal forming step;
• and
• the separation step includes a step of cutting the piezoelectric layer, the support substrate, the first cover, and the second cover along the borders of the divided regions.

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

• a first substrate preparing step of preparing a first substrate including a piezoelectric layer including a first principal surface and a second principal surface that face in opposite directions, at least one pair of electrodes formed on the first principal surface to oppose each other in an intersecting direction that intersects a thickness direction of the piezoelectric layer, a tabular support substrate formed on the second principal surface, and a first metallic frame formed on the first principal surface so as to surround the piezoelectric layer and the at least one pair of electrodes;
• an inorganic sheet preparing step of forming a second metallic frame on an inorganic sheet;
• a joining step of overlaying the first substrate and the inorganic sheet on each other such that the inorganic sheet covers the at least one pair of electrodes and joining the first metallic frame and the second metallic frame together, the joining step being carried out after the first substrate preparing step and the inorganic sheet preparing step;
• a first cavity forming step of forming a first cavity in the tabular support substrate by etching after the joining step;
• and
• a resin sheet forming step of providing a resin sheet on the tabular support substrate so as to close the first cavity after the first cavity forming step.

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

• an intermediate product preparing step of preparing an intermediate product including a piezoelectric layer including a first principal surface and a second principal surface that face in opposite directions, at least one pair of electrodes formed on the first principal surface and opposing each other in an intersecting direction intersecting a thickness direction extending perpendicularly or substantially perpendicularly to the first principal surface, wiring electrodes formed on the first principal surface and electrically connected to respective ones of the at least one pair of electrodes, and a support substrate formed on the second principal surface and including a first cavity that is formed through the support substrate so as to overlap at least a portion of the at least one pair of electrodes as viewed in the thickness direction;
• a first cover forming step of providing a first cover on the support substrate so as to close the first cavity after the intermediate product preparing step;
• a support frame forming step of forming a support frame including a second cavity after the first cover forming step;
• a second cover forming step of providing a second cover on the support frame so as to close the second cavity after the support frame forming step;
• a terminal hole forming step of forming terminal holes through the support frame and the second cover or through the support substrate and the first cover after the second cover forming step;
• an under-bump metal forming step of forming under-bump metal bodies in respective terminal holes after the terminal hole forming step;
• and
• a bump forming step of forming bumps on respective under-bump metal bodies after the under-bump metal forming step.

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

• an intermediate product preparing step of preparing an intermediate product including a piezoelectric layer including a first principal surface and a second principal surface that face in opposite directions, at least one pair of electrodes formed on the first principal surface and opposing each other in an intersecting direction intersecting a thickness direction extending perpendicularly or substantially perpendicularly to the first principal surface, wiring electrodes formed on the first principal surface and electrically connected to respective ones of the at least one pair of electrodes, and a support substrate formed on the second principal surface and including a first cavity that is formed through the support substrate so as to overlap at least a portion of the at least one pair of electrodes as viewed in the thickness direction;
• a support frame forming step of forming a support frame including a second cavity after the intermediate product preparing step;
• a cover forming step of providing a first cover on the support substrate so as to close the first cavity and providing a second cover on the support frame so as to close the second cavity, the cover forming step being carried out after the support frame forming step;
• a terminal hole forming step of forming terminal holes through the support frame and the second cover or through the support substrate and the first cover after the cover forming step;
• an under-bump metal forming step of forming under-bump metal bodies in respective terminal holes after the terminal hole forming step;
• and
• a bump forming step of forming bumps on respective under-bump metal bodies after the under-bump metal forming step.