Detlev Richter

How we test Siemens Embedded DRAM Cores

The techniques used to test Siemens Embedded DRAM Cores are described. Test Isolation and Design-For-Test logic is built in to the core interface, while external access and Algorithmic Pattern Generation are handled by a central Test Controller. All tests used for standard DRAMs can be applied to the DRAM cores, but only a subset of these are used for any given product.

Simulation based analysis of temperature effect on the faulty behavior of embedded DRAMs

Temperature has proven to be an effective stress condition, commonly used to stress memory devices and to detect special types of failure mechanisms. In this paper a new approach is presented where temperature is used as a test parameter to increase the fault coverage of specific tests. This is done using defect injection and simulation of a memory model at different temperatures. The analysis presents new types of detection conditions for memories and evaluates the impact of temperature on these conditions.

A memory specific notation for fault modeling

This paper shows the shortcomings of the current, generic notation for fault models and extends it to allow the description of fault models for DRAMs. The advantage is that the extended fault models can easily be translated into operation sequences and tests that detect the described fault. Examples are given to show that the new notation results in optimized, memory specific, tests that have a shorter run time for a given fault coverage.

Optimizing Stresses for Testing DRAM Cell Defects Using Electrical Simulation

Stresses are considered an integral part of any modern industrial DRAM test. This paper describes a novel method to optimize stresses for memory testing, using defect injection and electrical simulation. The new method shows how each stress should be applied to achieve a higher fault coverage of a given rest, based on an understanding of the internal behavior of the memory. In addition, results of a fault analysis study, performed to verify the new optimization method, show its effectiveness.