Electrostatic discharge failure factor of LSIs and a new method for measuring it

et al. 1998

In the charged device model (CDM) test, the relationship between the failure voltage, the capacitance of LSIs and the failure charge was made clear by a new CDM tester. The mobile charge measurement apparatus was fabricated in the tester, and the capacity and the charge could be measured simultaneously in the CDM test. The CDM sensitivity of the logic MOS LSIs was represented as an inherent quantity of charge for each LSI. Furthermore, using the experimental results, a basic protection circuit to withstand the high quantity of charge in the CDM test was described. The practical use of the data gives us methods to prevent electrostatic discharge (ESD) trouble for quarter-micron LSIs.

Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new CDM test method and protective circuits against the excessive mobile charge

et al. 1998

“…When the LSI was held with tweezers, the time constant of the circuit must increase in proportion to the sum of C LG ( 5 pF) and the capacity C T W ( 5 pF) of the tweezers. These capacities were obtained immediately by measuring the mobile charge Q EM with the Coulomb meter using the method of a previous paper [6] after having supplied the same voltage as the charged person to the pair of isolated tweezers or the isolated LSI. The time constant of the transient response for a very short time, of the order of a nanosecond, is described with C = 5 pF instead of C = 100 pF.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we investigated the relationship of the CDM failure voltage V D to the device capacitance C LG between an inner conductor in a Logic MOS LSI and the ground plane [6]. Simultaneously, we defined the charge in the C LG as the excessive mobile charge Q EM .…”

Section: Introductionmentioning

confidence: 99%

“…First, focusing on the nanosecond current transient, we will investigate the discharge characteristics between a pin of an LSI held by a charged person and the ground plane. Next, we will determine the capacity C LG by using an apparatus for measuring excessive mobile charge (the Coulomb meter) discussed in a previous paper [6]. Then, we will be able to express the discharge characteristic as the L-C-R series circuit.…”

Section: Introductionmentioning

confidence: 99%

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Problems of the human body model and electrostatic discharge part 1: discharge from LSIs held by a charged person

et al. 1998

The nanosecond transient response between a pin of a large-scale integrated circuit (LSI) held by a charged person and the ground plane showed a very sharp impulse and high peak current. This response could not be represented using the human body model (HBM), and it was caused by the parasitic capacity between an inner conductor in the LSI and the ground plane. However, the conventional HBM tester could not control the low capacitance. Consequently, the machine model (MM) using a low capacitance or the charged device model (CDM) with low device capacitance should be used. Moreover, the capacitanc of charged objects including LSIs can be determined by a Coulomb meter. Practical use of these data will give us the methods to prevent electrostatic discharge troubles for quarter-micron LSIs.

The use of the coulomb meter to measure the excess mobile charge and capacitance of LSI circuits in the charged device model

et al. 1998

The conventional charged device model (CDM) test methods for large-scale integrated (LSI) circuits have not prescribed the device capacitance; furthermore, the CDM sensitivity has been represented by the withstand voltage. Also, a method for measuring the voltage of small objects such as LSI circuits has not been established. For these reasons, the failure voltages obtained with every kind of tester have varied, and it could not be judged whether the charged LSI circuit would fail or not in CDM events. To solve these problems, we defined the failure factor as the excess mobile charge which could be measured by the newly developed coulomb meter. In addition, we developed a new CDM tester with the coulomb meter and obtained the excess mobile charge and the device capacitance. The CDM tester showed that several logic MOS LSI circuits failed at their inherent constant charge. However, when the charge in low capacities was measured by the coulomb meter, the internal circuit showed a step transient response. This problem could be alleviated considerably by replacing the metal probe with a ceramic one. By using this coulomb meter, we investigated the basic characteristics of the device capacitance. Consequently, the device capacitance versus the distance between the LSI circuit and the ground plane and the relationship between each pin's capacitance and the applied voltage became clear. In conclusion, the basic failure factors in the CDM could be made clear; then it could be judged by the coulomb meter whether the charged LSI circuits would fail or not in CDM events.