Semiconductor device having variable parameter selection based on temperature and test method
View Patent ↗A semiconductor device that may include temperature sensing circuits is disclosed. The temperature sensing circuits may be used to control various parameters, such as internal regulated supply voltages, internal refresh frequency, a word line low voltage, or the like. In this way, operating specifications of a semiconductor device at worst case temperatures may be met without comprising performance at normal operating temperatures. Each temperature sensing circuit may include a selectable temperature threshold value as well as a selectable temperature hysteresis value. In this way, temperature performance characteristics may be finely tuned. Furthermore, a method of testing the temperature sensing circuits is disclosed in which a current value may be monitored and temperature threshold values and temperature hysteresis values may be thereby determined.
1. A method of testing a temperature sensing circuit in a semiconductor device, comprising the steps of:
placing the semiconductor device in a mode of operation;
providing a temperature to the semiconductor device;
performing a first current measurement of the semiconductor device,
incrementing the temperature of the semiconductor device; and
performing a second current measurement of the semiconductor device;
wherein a step increase in current from the first current to the second current indicates a first temperature threshold value of the temperature sensing circuit.
2. The method of testing a temperature sensing circuit in the semiconductor device of claim 1 , further including the steps of:
performing a third current measurement of the semiconductor device;
decrementing the temperature of the semiconductor device; and
performing a fourth current measurement of the semiconductor device;
wherein a step decrease in current from the third current measurement of to the fourth current indicates a second temperature threshold of the temperature sensing circuit wherein a temperature hysteresis value is essentially the first temperature threshold minus the second temperature threshold.
3. The method of testing the temperature sensing circuit in the semiconductor device of claim 1 , wherein:
the semiconductor device is a semiconductor memory device.
4. The method of testing the temperature sensing circuit in the semiconductor device of claim 1 , wherein:
the semiconductor device is a dynamic random access memory.
5. The method of testing the temperature sensing circuit in the semiconductor device of claim 4 , wherein:
the mode of operation is a self-refresh mode.
6. A method of testing a temperature sensing circuit in a semiconductor device, comprising the steps of:
providing a temperature to the semiconductor device;
performing a first current measurement of the semiconductor device;
changing the temperature of the semiconductor device in a first direction; and
performing a second current measurement of the semiconductor device;
wherein a step change in current from the first current to the second current indicates a first temperature threshold value of the temperature sensing circuit.
7. The method of testing a temperature sensing circuit in the semiconductor device of claim 6 , further including the steps of:
performing a third current measurement of the semiconductor device;
changing the temperature of the semiconductor device in an opposite direction; and
performing a fourth current measurement of the semiconductor device;
wherein a step change in current from the third current measurement of to the fourth current indicates a second temperature threshold of the temperature sensing circuit wherein a temperature hysteresis value is essentially the first temperature threshold minus the second temperature threshold.
8. The method of testing the temperature sensing circuit in the semiconductor device of claim 6 , wherein:
the semiconductor device is a semiconductor memory device.
9. The method of testing the temperature sensing circuit in the semiconductor device of claim 6 , wherein:
the semiconductor device is a dynamic random access memory.
10. A method of testing a temperature sensing circuit in a semiconductor to device, comprising the steps of
changing the temperature of the semiconductor device; and
monitoring an operating parameter of the semiconductor device;
wherein the operating Parameter is monitored for a step change to indicate a predetermined temperature has been detected by the temperature sensing circuit.
11. The method of testing the temperature sensing circuit in the semiconductor device of claim 10 , wherein the operating parameter is a current value.
12. The method of testing the temperature sensing circuit in the semiconductor device of claim 10 , wherein:
the test is performed while the semiconductor device is integrally contained on a silicon wafer with a plurality of like semiconductor devices.
13. The method of testing the temperature sensing circuit in the semiconductor device of claim 10 , wherein:
the test is performed on a packaged semiconductor device.
14. The method of testing the temperature sensing circuit in the semiconductor device of claim 10 , wherein:
the semiconductor device is a memory device.
15. The method of testing the temperature sensing circuit in the semiconductor device of claim 10 , wherein:
the semiconductor device is a dynamic random access memory device.
16. The method of testing the temperature sensing circuit in the semiconductor device of claim 15 , wherein:
the operating parameter is a current value.
17. The semiconductor device of claim 15 , wherein:
the operating parameter is an average current value.