Patent ID: 7522968

Claim:
A method for increasing the processing throughput of multiple lots of semiconductor wafers through a cluster tool while maintaining a constant wafer history for each lot, comprising: defining a first substrate processing sequence that has two or more processing steps; defining a second processing sequence that has two or more processing steps, wherein at least one of the processing steps in the second substrate processing sequence has a processing time that is different than all of the processing steps within the first substrate processing sequence or the second substrate processing sequence has a different number of processing steps than the first substrate processing sequence; processing a first batch of substrates in the cluster tool using the first substrate processing sequence; processing a second batch of substrates in the cluster tool using the second substrate processing sequence, wherein the start of the first process step on the first substrate in the second batch is controlled relative to the start of the first process step on the last substrate in the first batch of substrates so that each substrate in the first batch of substrates has the same processing time for each processing step in the first substrate processing sequence, each substrate in the second batch of substrates has the same processing time for each processing step in the second substrate processing sequence, the relative time between each of the processing steps that each substrate in the first batch experiences is generally constant, and the relative time between each of the processing steps that each substrate in the second batch experiences is generally constant; transferring each substrate of the first batch of substrates and the second batch of substrates through the cluster tool using a first robot assembly at a maximum robot limited throughput for the first substrate processing sequence and the second substrate processing sequence; and implementing skip steps in the first substrate processing sequence and the second substrate processing sequence when sending each of the first batch of substrates and the second batch of substrates through the cluster tool such that an average substrate throughput of the cluster tool is equal to or greater than an average substrate throughput of a subsequent processing tool.