A micromachined device (32) receiving a pressurizable fluid has a plurality of layers (34, 36) bonded together along at least one bond interface (35), the bond interface having a terminus bordering the pressurizable fluid. In a vicinity of at least one bond interface (35) at least one layer (34, 36) has a shape that reduces a stress magnitude near the bond terminus. In a preferred embodiment a width of at least one layer (34) increases toward the bond interface (35), to increase the pressure at which the device can operate without fracturing. In another embodiment, both layers (34, 36) bordering the bond interface (35) have widths in the vicinity of the bond interface (35) that increase toward the bond interface (35). Alternately, the layers (34, 36) have walls shaped such that, for a reference line perpendicular to the bond interface (35) and passing through an end of the bond interface (35) bordering the cavity, the cavity protrudes between the reference line and at least one of the walls.