the bonding step before it is connected to the first wafer 35 the second wafer 36 is provided by etching with passage holes 40 for the equalization chambers 19 21 22 and 23 and is also provided with a rectangular passage hole 41 to receive the first wafer 35 as a single disk such that connecting webs 42 and 43 remain the dot dash lines in fig3 indicate the outer contours of the individual pressure difference sensors at the conclusion of the manufacturing process however at an initial step in the process stage shown in the drawing only a wafer sandwich consisting of the first and second wafers 35 and 36 is present in this sandwich partial cuts 44 which extend at an acute angle to the lengthwise direction of the rectangular passage hole 41 are made the partial cuts 44 are so deep that they completely cut through the second wafer 36 as a result the webs 43 of the second wafer 36 are separated from the other parts of the second wafer 36 and from the region 45 shown hatched in fig3 thereupon in a further manufacturing step a third wafer 46 shown in dash dot line in fig4 is bonded to the wafer sandwich which has been produced from the first and second wafers 35 and 36 the third wafer 46 has several upper bearing parts 3 in accordance with fig1 in.