# US 7,103,861 B2 · Test structure for automatic dynamic negative-bias temperature instability testing

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- Number: US 7,103,861 B2
- Document ID: US7103861B2
- Status: Granted
- Kind: B2
- Application number: 10/864,951
- Filed: 2004-06-10
- Published: 2005-12-15
- Granted: 2006-09-05
- Earliest claimed: 2004-06-10
- Assignees: Chartered Semiconductor Manufacturing Ltd.
- Inventors: Chew Hoe Ang; Gang Chen; Shyue Seng Tan
- Web page: https://patentgrep.com/patent/US7103861B2

## CPC

- H10P 74/277: {Circuits for electrically characterising or monitoring manufacturing processes, e.g. circuits in tested chips or circuits in testing wafers}
- G01R 31/2628: {for measuring thermal properties thereof}
- G01R 31/2642: {Testing semiconductor operation lifetime or reliability, e.g. by accelerated life tests}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

The invention describes a novel test structure and process to create the structure for performing automatic dynamic stress testing of PMOS devices for Negative Bias Temperature Instability (NBTI). The invention consists of an integrated inverter, two integrated electronic switches for switching from stress mode to device DC characterization measurement mode, and a PMOS FET device under test (DUT). The inverter assures the proper 180 degree phase relationship between the test device source and gate voltage while the imbedded electronic switches provide isolation of the test device during DC characterization testing. Another embodiment of the invention enables the testing of multiple devices under test (DUT's).

## Claims

### Claim 1

A method of generating a reduced capacitance semiconductor test structure on a substrate to provide for the automatic dynamic stress and device characterization test of semiconductor devices for Negative Bias Temperature instability said method comprising:
creating an imbedded semiconductor device inverter with a PMOS device and a NMOS device to provide a 180 degree phase shift output from the circuit input dynamic stress test first voltage Vpulse;
creating first and second imbedded NMOS electronic switch devices;
creating a first PMOS test device for dynamic NBTI stress and device characterization;
providing the circuit with a second voltage Vdd, a third voltage Vss, a fourth voltage Vd, a fifth voltage Vc, and a sixth voltage Vg;
creating terminal access pads said first Vpulse, second Vdd, third Vss, fourth Vd, fifth Vc and sixth Vg voltage sources.

### Claim 2 (depends on 1)

The method according to claim 1 whereby said semiconductor device inverter is created by connecting the gates of said inverter PMOS and said inverter NMOS together and to said input dynamic stress test first voltage Vpulse which consists of a pulse train of periodic high and low amplitude square waves.

### Claim 3 (depends on 1)

The method according to claim 1 whereby said semiconductor device inverter is powered by connecting said inverter PMOS device source element to said second voltage source Vdd, and by connecting said inverter NMOS source element to said third voltage source Vss, typically ground.

### Claim 4 (depends on 1)

The method according to claim 1 whereby said semiconductor device inverter output is formed by connecting the drains of said inverter PMOS and said inverter NMOS together.

### Claim 5 (depends on 1)

The method according to claim 1 whereby said electronic switch devices are controlled by connecting the gates of said switches together and to said fifth voltage source, Vc, which is raised to the level of said second voltage source, Vdd, to turn said switches on, and changed to a negative voltage level to turn said switches off.

### Claim 6 (depends on 1)

The method according to claim 1 whereby said input dynamic stress test said first voltage Vpulse is applied to the source of said first PMOS test device by connecting said first voltage Vpulse to the source of said first electronic switch, by connecting the drain of said first electronic switch to the source of said first PMOS test device, connecting the drain of said first PMOS test device to said third voltage Vss, and by turning on said first electronic switch with said forth voltage source Vc.

### Claim 7 (depends on 1)

The method according to claim 1 whereby said inverter output is applied to the gate of said first PMOS test device by connecting said inverter output to the drain of said second electronic switch and connecting the source of said second electronic switch to said gate of said first PMOS test device and by turning on said second electronic switch concurrently with said first electronic switch with said fifth voltage source, Vc.

### Claim 8 (depends on 1)

The method according to claim 1 whereby said first PMOS test device is characterized by connecting said fourth voltage Vd to said first PMOS test device source, connecting said sixth voltage Vg to said first PMOS test device gate, turn off said first and second electronic switches by reducing said fifth voltage source Vc to a negative level, and by providing the appropriate measurement conditions for said fourth and sixth voltages.