Substrate processing apparatus and method of manufacturing semiconductor device

A substrate processing apparatus comprising:

• a reaction vessel configured to process substrates therein;
• a first induction target part comprising a peripheral portion and a center portion wherein a thickness of the center portion is less than that of the peripheral portion, the first induction target part being configured to heat the substrate accommodated on the center portion;
• a second induction target part comprising a peripheral portion and a center portion wherein a thickness of the center portion is less than that of the peripheral portion such that a thickness of a portion between the center portion and the peripheral portion of the second induction target part gradually decreases, or the thickness of the center portion is greater than that of the peripheral portion such that the thickness of the portion between the center portion and the peripheral portion of the second induction target part gradually increases, the second induction target part being configured to heat the substrate accommodated on the center portion of the first induction target part;
• and
• an induction target part holder configured to hold the first induction target part and the second induction target part in a manner that the second induction part is spaced apart from the first induction target part by a predetermined distance;
• and
• an induction heating device configured to heat at least the first and second induction target parts which are provided in the reaction vessel and held by the induction target part holder, by using an induction heating method.