| CPC H01L 21/68792 (2013.01) [C23C 16/4583 (2013.01); H01L 21/67303 (2013.01); H01L 21/67306 (2013.01); H01L 21/67745 (2013.01); H01L 21/67757 (2013.01); H01L 21/67069 (2013.01); H01L 21/67115 (2013.01); H01L 21/68785 (2013.01)] | 12 Claims | 

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               1. A substrate processing apparatus, comprising: 
            a first boat configured to hold substrates in a shelf shape; 
                a second boat provided coaxially with the first boat and configured to hold substrates in a shelf shape; and 
                a drive configured to rotate the first boat and the second boat in a synchronized manner and configured to raise and lower the second boat relative to the first boat, 
                wherein the drive includes: 
                a substantially cylindrical fixed sleeve; 
                a substantially cylindrical rotary shaft inserted into the fixed sleeve with a gap left therebetween and configured to rotate relative to the fixed sleeve; 
                a substantially cylindrical outer support configured to support the first boat; and 
                an outer connector configured to connect the rotary shaft and the outer support, 
                wherein the rotary shaft and the outer support are made of materials having different thermal expansion coefficients, and 
                wherein the outer connector includes a hub made of a material having a thermal expansion coefficient between the thermal expansion coefficient of the material constituting the rotary shaft and the thermal expansion coefficient of the material constituting the outer support. 
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