with excellent properties on multiple fine substrates 540 by transferring to the fine substrates 540 layers 530 including transistor circuits and formed on a substrate 531 with a separation layer 532 interposed therebetween the semiconductor element forming process of the invention is not limited to the embodiments illustrated in fig1 a 9 but may be modified without departing from the technical scope of the invention although in the embodiment shown in fig3 a 3c for example the semiconductor element and its circuit are specifically a mosfet and its circuit the semiconductor can be an amorphous silicon tft shown in fig5 a 5c a solar battery element shown in fig6 a 6c a bipolar element an amorphous image sensor etc although in the embodiments illustrated in fig3 a 7 transfer is performed after the completion of at least the transistor element it can be performed even during the manufacture of the element fig1 illustrates a removal process using etching as a process for removing the separation layer in this case a film structure 30 consisting of a single layer or plural layers is separated from a substrate 10 by decomposing the separation layer using a solution or a gas for dissolving the separation layer.