A method of processing a liquid discharge head substrate includes the step of providing a recessed portion in the back surface of the substrate by discharging a manufacturing liquid in a linear trajectory to the back surface of the substrate and by irradiating the back surface of the substrate with laser light that passes along and in the manufacturing liquid. More particularly, the present invention provides an organometallic precursor containing a hydrazine-based compound coordinated with a central metal thereof, and a method of forming a metal film or pattern using the same. At least one of the amino acid residues has a positive charge.