expected that the film will be deformed due to a load caused by gravity or inertial force during transportation or movement. The deflection strength of the silicon thin film depends on physical properties, including Young's modulus, and the area of the thin film region. Generally, the strength of the film is proportional to the cube of the film thickness. Therefore, making the film thickness of the stencil mask 1005 thicker enables the strength to increase, which prevents the stencil mask 1005 being deformed as a result of the ion implantation described above.
On the other hand, as described above, the openings 1004 in the stencil mask 1005 are made by processing the SOI substrate 1000 by anisotropic etching. Therefore, the accuracy of the openings 1004 in the stencil maskof the stencil mask is T, each of the opening dimension of the stencil mask and the dimension of the implantation region of the substrate to be processed is S1, and the dimension of the region of the substrate into which charged particles are implanted is S2, S2 is expressed by the following equation:S2=S1−T·tan θ
As seen from the above equation, of the region S1 into which ions are supposed to be implanted, only the region expressed by T·tan θ is cut off by the stencil mask. The larger the incident angle becomes, the larger the cut-off region becomes. In addition, the thicker the film thickness T of the stencil mask, the larger the cut-off region becomes. For this reason, it is impossible to secure the desired implantation region