Compared to the above approaches, in the embodiments of the present disclosure, the weight measurement is performed before and after the deposition process. The thickness is calculated from the weight measured by the weight measurement. The status of the deposition process is able to be known immediately after the deposition process is finished. Alternatively stated, the thickness measurement is a real-time measurement. It provides a real-time monitor to the deposition process. Therefore, when a wafer is processed under a deposition process identified as “FAIL”, the user or the system is able to recognize that the wafer is potential to be bad. The user or the system is able to stop the following processes to the wafer. Accordingly, the waste of time and the resource of the processes for the bad wafers are able to be prevented.

The above illustrations include exemplary operations, but the operations are not necessarily performed in the order shown. Operations may be added, replaced, changed order, and/or eliminated as appropriate, in accordance with the spirit and scope of various embodiments of the present disclosure. For example, in various embodiments, the operations S420-S424 are able to be operated before or in parallel with the operation S416.