Substrate transport apparatus and substrate transport method

A substrate processing system, comprising:

• a substrate transport apparatus comprising a base, a holding device configured to retract relative to the base and hold a plurality of substrates in a plurality of stages in a vertical direction, respectively, a temporary loading device configured to store the plurality of substrates held by the holding device, a detection device comprising three detection components such that the three detection components are positioned to detect peripheries of the substrates from different positions, respectively, while the substrates are being held in the stages in the vertical direction by the holding device;
• and
• a control device comprising circuitry configured to estimate a position of the substrates held in the stages in the vertical direction based on detection result of the detection device, calculate an amount of shifting in a horizontal direction between a base position and the position of the substrates held in the stages in the vertical direction, determine whether the amount of shifting is within a threshold value, and execute transport of the substrates held by the holding device when the amount of shifting is determined to be within the threshold value
• wherein the circuitry of the control device is configured to control the holding device such that when the amount of shifting exceeds the threshold value, the holding device holds one of the substrates and the temporary loading device stores the other substrates and that the detecting device detects the periphery of the one of the substrates held by the holding device, calculate an amount of shifting of the one of the substrates from the base position based on detection result of the detecting device, and control the holding device such that the holding device changes a position based on the amount of shift to match a position of the one of the substrates with the base position.

A method for transporting substrates, comprising:

• holding a plurality of substrates such that a holding device configured to retract relative to the base holds the plurality of substrates in a plurality of stages in a vertical direction, respectively;
• detecting peripheries of the substrates held by the holding device such that a detection device comprising three detection components detects the peripheries of the substrates from different positions, respectively, while the substrates are being held in the stages in the vertical direction by the holding device;
• estimating a position of the substrates held in the stages in the vertical direction based on detection result of the detection device;
• calculating an amount of shifting in a horizontal direction between a base position and the position of the substrates held in the stages in the vertical direction;
• determining whether the amount of shifting is within a threshold value;
• and
• executing transport of the substrates held by the holding device when the amount of shifting is determined to be within the threshold value,
• wherein when the amount of shifting exceeds the threshold value, the holding device holds one of the substrates and a temporary loading device configured to store the plurality of substrates held by the holding device stores the other substrates, the detecting device detects the periphery of the one of the substrates held by the holding device, an amount of shifting of the one of the substrates from the base position is calculated based on detection result of the detecting device, and the holding device changes a position based on the amount of shift to match a position of the one of the substrates with the base position.