Process for producing liquid ejection head

A process for producing a liquid ejection head comprising:

• a provision step of providing a piezoelectric substrate, and a first support substrate and a second support substrate for supporting the piezoelectric substrate;
• a step of forming a first mark and a first electrode positioned using the first mark as a reference on one principal surface of two principal surfaces of the piezoelectric substrate;
• a step of forming an electrode pad on the other principal surface of the two principal surfaces of the piezoelectric substrate to electrically connect the first electrode to the electrode pad and forming a second mark positioned using the first mark as a reference on the other principal surface;
• a step of bonding one surface of the first support substrate to said one principal surface of the piezoelectric substrate;
• a step of forming a groove positioned using the second mark as a reference in the other principal surface;
• a step of forming a second electrode electrically separated from the first electrode on at least one surface of a lateral surface of the groove, a bottom surface of the groove and the other principal surface remaining after the groove is formed;
• a joining step of joining one surface of the second support substrate to the other principal surface of the piezoelectric substrate;
• and
• a separation step of separating the first support substrate from the piezoelectric substrate.