Vanguard International Semiconductor Corporation

Christopher Ematrudo

Michael C Stephens, Jr

Luigi Ternullo, Jr

Jeffrey Scott Earl

Michael F Vincent

A new method of detecting a reticle option layer in an integrated circuit device has been achieved. The method may be applied to detect the presence of the threshold voltage implantation reticle option layer by direct die probing or by probing a pin of a package integrated circuit. The current through a first MOS transistor is measured by forcing a test voltage on the drain and the gate. The gate and the drain of the first MOS transistor are connected together while the source is connected to a reference voltage. The first MOS transistor has the standard threshold implantation but not the threshold voltage reticle option. The current through a second MOS transistor is measured by forcing the same test voltage on the drain and the gate. The gate and said drain of the second MOS transistor are connected together while the source is connected to a reference voltage. The second MOS transistor has the standard threshold voltage implantation and the threshold voltage implantation reticle option layer. The current through the first NMOS transistor and the current through the second MOS transistor are compared to detect the presence of the threshold voltage implantation reticle option layer in the integrated circuit device.

Reticle option layer detection method

A circuit for a DRAM is described which, when in test mode, notifies a tester when the self-refresh operation of a dynamic random access memory (DRAM) reaches various stages of completion. By signaling the tester when, i.e., &frac18;, &frac14;, &frac12;, etc. of the self-refresh cycle is reached, the amount of time needed for verification of the self-refresh oscillator frequency is reduced correspondingly by a factor of 8, 4, 2 etc. The signaling of a partial test time is achieved by adding self-refresh status logic circuits which decode the high order most significant bits of the refresh address counter. The activation of the third most significant bit signals completion of &frac18;th of the self-refresh cycle, the activation of the second most significant bit signals completion of &frac14;th of the self-refresh cycle, the activation of the most significant bit signals completion of &frac12; of the self-refresh cycle, and deactivation of the most significant bit signals completion of the self-refresh cycle.

Self-refresh test time reduction scheme

A burst-mode capable RAM chip includes a timing circuit for clocking a burst counter during a burst transfer. In response to an input indicating the beginning of the burst transfer, the timing circuit generates a first signal that loads the initial address of the burst transfer into the latches of a burst counter. Then, the timing circuit generates a second signal to increment the burst counter to the second address in the burst transfer after the load of the initial address has successfully completed but prior to the second clock cycle. Finally, the timing circuit generates subsequent signals to increment the burst counter through the remaining addresses of the burst transfer. Each of the subsequent signals is generated in response to an input from the system clock.

Timing circuit for a burst-mode address counter

A timing scheme for multiple data clock activation with programmable delay for use in accessing a multiple CAS latency memory device. A multi-stage data propagation path is used to propagate a bit being accessed from a memory array of the device to an output line. Timing signals are generated so that in a CAS latency three mode, the timing signal that activates the next to last stage of the propagation path is triggered by an output clock signal that activates the last stage of the propagation path so that pulse from the output clock signal does not overlap with pulses of the timing signal that activates the previous stage. This timing scheme ensures the data lines feeding the last stage are not being restored while the last stage is sensing these data lines. A programmable delay circuit is used to adjust the timing of the output clock signal.

Growing community of inventors

Campbell, CA, United States of America

Christopher Ematrudo