Substrate transfer method and processing system

A substrate transfer method for sequentially transferring a substrate between a heat treatment chamber and another chamber different from the heat treatment chamber by using a transfer unit having a first pick and a second pick, the method comprising:

• a first process of holding an unprocessed substrate by the first pick and transferring the unprocessed substrate to the heat treatment chamber;
• a second process of holding a processed substrate, which has been subjected to heat treatment in the heat treatment chamber, by the second pick, unloading the processed substrate from the heat treatment chamber, and loading the unprocessed substrate held by the first pick into the heat treatment chamber;
• a third process of transferring the processed substrate held by the second pick to said another chamber;
• and
• a fourth process of holding an unprocessed substrate in said another chamber by the first pick, loading the processed substrate held by the second pick into said another chamber, and then putting both the first pick and the second pick into a state of not holding a substrate.