Stress insensitive integrated circuit

DETAILED DESCRIPTION Accordingly, it is an object of this invention to provide an improved integrated circuit structure in which changes in circuit performance induced by mechanical stresses of the structure are minimized.
It is a further object of the invention to provide a technique for incorporating critical circuit elements of a normally stress-sensitive type into an integrated circuit without making the integrated circuit stress sensitive.
It is another object of the invention to provide an integrated circuit including surface effect devices which is not sensitive to mechanical stresses induced in packaging the circuit.
It is yet another object of the invention to provide linear integrated circuits including circuit elements with a critical matching or ratio relationship and which are subject to performance changes due to mechanical stress, in which the matching or ratio relationship is maintained despite changes in the mechanical stress of the integrated circuit after the critical circuit elements have been fabricated.
It is still another object of the invention to provide an operational amplifier integrated circuit including a JFET input stage having a substantially reduced input offset voltage shift produced by packaging the integrated circuit.
The attainment of these and related objects may be achieved through use of the novel integrated circuit disclosed herein.
An integrated circuit in accordance with the invention includes a plurality of circuit elements interconnected to operate as a circuit and formed in a common semiconductor substrate.
The semiconductor substrate is mounted in a supporting package.
As a result of being mounted in the package, the semiconductor substrate has a mechanical stress which is symmetrical about at least one given axis.
At least those of the circuit elements with operating characteristics which are altered by mechanical stress are arranged symmetrically about at least one given axis.
In particular, transistor and resistor pairs which interact in operation of the circuit and which require a matched or ratio relationship between them are arranged in corresponding positions on either side of the axis of mechanical stress symmetry