Substrate processing apparatus

A substrate processing apparatus configured to carry out a predetermined process on a substrate, the substrate processing apparatus comprising:

• a processing tank storing a processing liquid;
• a substrate holder configured to support an outer peripheral edge portion of the substrate and retain a plurality of the substrates so that the plurality of the substrates are arranged in a normal direction of a substrate surface and are each in an upright orientation;
• and
• a substrate raising and lowering motor configured to raise and lower the substrate holder between a first position where the substrate is immersed in the processing liquid inside the processing tank and a second position where the substrate is located outside the processing tank, wherein
• the substrate holder is provided with at least a first retaining arm, a second retaining arm, and a fixation arm retaining the first retaining arm and the second retaining arm,
• with respect to a plane with a normal direction thereof extending in a horizontal direction, the plane including a line crossing centers of the plurality of the substrates retained by the substrate holder, the first retaining arm is disposed on one side of the plane, and the second retaining arm is disposed on the other side of the plane,
• the first retaining arm and the second retaining arm each include
• a retaining body having a bar shape and a side surface on which a fixation hole is formed,
• an inner support plate disposed on a side surface of the retaining body which side surface is closer to the plane and having a side surface on which a fixation hole is formed,
• an outer support plate disposed on a side surface of the retaining body which side surface is farther from the plane and having a side surface on which a fixation hole is formed, and
• a bolt and a nut that fix the retaining body, the inner support plate, and the outer support plate through the fixation holes,
• the bolt is disposed on a side closer to the plane with respect to the retaining body, and
• the nut is disposed on a side farther from the plane with respect to the retaining body.