The present invention provides a spool holding device. A modified capacity is determined, wherein a capacity is defined by a total of available channel coding elements per transmission time interval on a channel dedicated for transmitting the control information. The UEs are tracked as a scheduled portion and an unscheduled portion, wherein a UE is included in the scheduled portion in response to receiving a scheduling request from the UE. Offering or downloading of certain applications may be limited to only those visitors having consent from an enterprise administrator. The slave flip-flop receives and stores the output of the master flip-flop at the end of the memory operation based on the second clock signal. The method can advantageously control growth of impurities by further performing HF cleaning and baking after cleaning to minimize the amount of residual chemical ions generated during cleaning.