A semiconductor device comprises a first transistor connected between a bit line and a sense node, and a second transistor amplifying a signal of the sense node. Traffic interception modules connected to the network examine traffic exchanged between clients and servers on the network, recognize traffic associated with downloads of content from the network, and create content download descriptions describing the downloads. Hence, the protecting sheet is not ground while the reverse of the wafer is ground, and the grindstone is thus prevented from being clogged up with ground material of the protecting sheet.