mask 71 is made of a material of which enough etching selectivity to the al 2 o 3 film 63 can be ensured for example metal such as tin the hard mask 71 may be a film made of a material which is the same as that of the metal film 68 in addition the hard mask 71 is formed by pvd method next as shown in fig3 b the hard mask 71 is etched using the photoresist 70 a as an etching mask removing a portion thereof located in the region other than the lvp transistor region 40 r next as shown in fig3 c the al 2 o 3 film 63 is etched using the photoresist 70 a and the hard mask 71 as an etching mask removing a portion thereof located in the region other than the lvp transistor region 40 r here as shown in fig3 c even if the photoresist 70 a is etched and thereby vanished during the etching of the al 2 o 3 film 63 the al 2 o 3 film 63 having a desired size is formed by patterning because the hard mask 71 functions as an etching mask next as shown in fig3 d the insulating film 62 is etched using the hard mask 71 as an etching mask removing.