Integrated circuit with temperature-controlled component
An integrated circuit has a circuit component and a heating component thermally coupled together in a region thermally isolated from other parts of the integrated circuit. The thermal isolation can be provided by a bridge over a cavity in the substrate or caps over a thin substrate. A control circuit, which may be responsive to a sensing component thermally coupled to the heating component, controls the heating component to heat the circuit component to a temperature greater than that of the other parts of the integrated circuit, to control a temperature-dependent characteristic of the circuit component. The circuit component can for example be a resistor whose resistance is precisely determined and/or adjusted via the control circuit.
1 . An integrated circuit comprising a circuit component of the integrated circuit and a heating component thermally coupled together and relatively thermally isolated from other parts of the integrated circuit, and a control circuit for controlling the heating component for heating the circuit component to a temperature greater than a maximum operating temperature of said other parts of the integrated circuit.
2 . An integrated circuit as claimed in claim 1 wherein the thermally coupled components are provided on a bridge over a cavity in the integrated circuit to provide the relative thermal isolation of the thermally coupled components from said other parts of the integrated circuit.
3 . An integrated circuit as claimed in claim 2 wherein the control circuit is a part of the integrated circuit.
4 . An integrated circuit as claimed in claim 1 wherein the thermally coupled components are provided in a region of the integrated circuit having a relatively thin substrate and caps over said region to provide the relative thermal isolation of the thermally coupled components from said other parts of the integrated circuit.
5 . An integrated circuit as claimed in claim 4 wherein the control circuit is a part of the integrated circuit.
6 . An integrated circuit as claimed in claim 1 and including a sensing component thermally coupled to the heating component, wherein the control circuit is responsive to the sensing component for controlling the heating component.
7 . An integrated circuit as claimed in claim 6 wherein the thermally coupled components are provided on a bridge over a cavity in the integrated circuit to provide the relative thermal isolation of the thermally coupled components from said other parts of the integrated circuit.
8 . An integrated circuit as claimed in claim 7 wherein the control circuit is a part of the integrated circuit.
9 . An integrated circuit as claimed in claim 6 wherein the thermally coupled components are provided in a region of the integrated circuit having a relatively thin substrate and caps over said region to provide the relative thermal isolation of the thermally coupled components from said other parts of the integrated circuit.
10 . An integrated circuit as claimed in claim 9 wherein the control circuit is a part of the integrated circuit.
11 . An integrated circuit as claimed in claim 1 wherein the control circuit is responsive to a control voltage for controlling the heating component.
12 . An integrated circuit as claimed in claim 1 wherein at least one of the thermally coupled components comprises a resistor.
13 . A method of controlling a temperature-dependent characteristic of a circuit component of an integrated circuit, comprising the steps of:
thermally coupling the circuit component to a heating component and relatively thermally isolating the thermally coupled components from other parts of the integrated circuit; and
controlling the heating component to heat the thermally coupled components to a temperature greater than a maximum operating temperature of said other parts of the integrated circuit.
14 . A method as claimed in claim 13 and including the step of maintaining a substantially constant temperature of the thermally coupled components thereby to maintain said temperature-dependent characteristic of the circuit component substantially constant.
15 . A method as claimed in claim 14 wherein the circuit component comprises a resistor and the temperature-dependent characteristic comprises a resistance of the resistor.
16 . A method as claimed in claim 13 and including the step of controlling temperature of the thermally coupled components thereby to adjust said temperature-dependent characteristic of the circuit component.
17 . A method as claimed in claim 16 wherein the circuit component comprises a resistor and the temperature-dependent characteristic comprises a resistance of the resistor.
18 . An integrated circuit comprising:
a substrate including a cavity in the substrate and a bridge over the cavity;
a circuit component of the integrated circuit on the bridge whereby it is relatively thermally isolated from other parts of the integrated circuit not on the bridge; and
a heating component on the bridge, the heating component and the circuit component being relatively thermally coupled together, whereby the circuit component can be heated by the heating component to a temperature greater than a temperature of said other parts of the integrated circuit.
19 . An integrated circuit as claimed in claim 18 and including a sensing component on the bridge relatively thermally coupled to the heating component and the circuit component.
20 . An integrated circuit as claimed in claim 18 and including a control circuit for controlling the heating component thereby to control a temperature to which the circuit component is heated.
21 . An integrated circuit comprising:
a substrate having a region having caps providing relative thermal isolation of said region from other parts of the substrate;
a circuit component of the integrated circuit in said region whereby it is relatively thermally isolated from other parts of the integrated circuit not in said region; and
a heating component in said region, the heating component and the circuit component being relatively thermally coupled together, whereby the circuit component can be heated by the heating component to a temperature greater than a temperature of said other parts of the integrated circuit.
22 . An integrated circuit as claimed in claim 21 and including a sensing component in said region relatively thermally coupled to the heating component and the circuit component.
23 . An integrated circuit as claimed in claim 21 and including a control circuit for controlling the heating component thereby to control a temperature to which the circuit component is heated.
24 . A method of making an integrated circuit having a substrate with a region having caps providing relative thermal isolation of said region from other parts of the substrate, comprising the steps of:
providing a heating component and a circuit component of the integrated circuit in said region of a first wafer;
etching an underside of a cap in a second wafer;
contacting the first and second wafers to provide the cap over said region;
backside grinding the first wafer to produce a relatively thin substrate in said region;
etching an underside of a second cap in a third wafer; and
contacting the first and third wafers to provide the second cap under said region.