Processing method of silicon substrate, fabricating method of substrate for liquid ejection head, and fabricating method of liquid ejection head

A fabricating method of a substrate for a liquid ejection head comprising the steps of:

• bonding a first silicon substrate and a second silicon substrate facing the first silicon substrate while holding an intermediate layer having an opening between the first and second silicon substrates;
• filling to at least partly embed a closed space defined by at least one of the first and second silicon substrates and the opening with a filler;
• etching to form a liquid supply port penetrating the filler in the opening and the second silicon substrate from the first silicon substrate;
• and
• forming an ejection unit having an ejection port for ejecting liquid supplied through the liquid supply port.

A fabricating method of liquid ejection head comprising the steps of:

• bonding a first silicon substrate and a second silicon substrate facing the first silicon substrate while holding an intermediate layer having an opening between the first and second silicon substrates;
• filling to at least partly embed a closed space defined by at least one of the first and second silicon substrates and the opening with a filler;
• etching to form a liquid supply port penetrating the filler in the opening and the second silicon substrate from the first silicon substrate;
• and
• forming, on the second silicon substrate, a liquid ejecting unit including an ejection energy generating unit for generating ejection energy for ejecting liquid and an ejection port for ejecting liquid supplied through the liquid supply port by ejection energy of the ejection energy generating unit.