A method for determining conditions for forming a dielectric SiOCH film, includes: (i) forming a dielectric SiOCH film on a substrate under conditions; (ii) evaluating the conditions using a ratio of Si—CH3 bonding strength to Si—O bonding strength of the film as formed in step (i); (iii) if the ratio is 2.50 % or higher, confirming the conditions, and if the ratio is less than 2.50 %, changing the conditions by changing at least one of the susceptor temperature, the distance between upper and lower electrodes, the RF power, and the curing time; and (iv) repeating steps (i) to (iii) until the ratio is 2.50 % or higher.