Method of manufacturing a micro injecting device

A method of manufacturing a micro-injecting device, comprising the steps of:

• forming a membrane by the steps of:
• spin-coating a first polyamide acid solution on a protective film on a base plate to form a first organic film;
• drying and heat-treating the first organic film to form a first organic layer;
• spin-coating a second polyamide solution of different chemical composition from said first polyamide acid solution on said first organic layer to form a second organic film;
• drying and heat-treating the second organic film to form a second organic layer;
• and
• detaching the first organic layer and second organic layer as a membrane from the base plate;
• forming a heating resistor/heating chamber barrier layer assembly by the steps of:
• forming a heating resistor layer on a protective layer on a second base plate;
• forming an electrode layer contacting the heating resistor layer;
• spin-coating the second polyamide solution on the heating resistor layer and protective layer to form a third organic film;
• drying and heat-treating the third organic film to form a third organic layer;
• and
• photo-etching the third organic layer to form a heating chamber barrier layer having heating chambers;
• forming a nozzle plate/liquid chamber barrier layer assembly by the steps of:
• forming a nozzle plate on a protective film on a third base plate;
• spin-coating said first polyamide acid solution on said nozzle plate to form a fourth organic film;
• drying and heat-treating the fourth organic film to form a fourth organic layer;
• photo-etching the fourth organic layer to form a liquid chamber barrier layer having a liquid chamber;
• and
• separating the nozzle plate/liquid chamber barrier layer assembly from the third base plate;
• aligning the membrane with the heating resistor layer/heating chamber barrier assembly with said first organic layer touching said heating chamber barrier layer, and assembling at an elevated temperature and pressure to form a first assembly;
• and
• aligning the nozzle plate/liquid chamber barrier layer assembly with said first assembly, with said liquid chamber barrier layer touching said second organic layer and assembling at an elevated temperature and pressure to complete the micro-injection device.