Substrate Processing Apparatus and Producing Method of Semiconductor Device

A substrate processing apparatus, comprising:

• a processing chamber;
• a holding member to hold at least a plurality of product substrates in the processing chamber,
• a heating member to heat the substrates,
• a supplying member to alternately supply at least a first reactant and a second reactant into the processing chamber;
• an exhausting port opened to the processing chamber, and
• a control unit, wherein the control unit
• executes a processing of forming thin films on the substrates by supplying the first reactant into the processing chamber, removing a surplus of the first reactant after the first reactant has been adsorbed on the product substrates which are held by the holding member, subsequently supplying the second reactant into the processing chamber, to cause the second reactant to react with the first reactant which has been adsorbed on the substrates, and
• executes the processing of forming the thin films in a state where a number of the product substrates is insufficient when a number of the product substrates to be held by the holding member is less than a maximum number of the product substrates which can be held by the holding member.