摘要:
A method for classifying patterns of failcodes on a semiconductor wafer, in accordance with the present invention, includes determining failcodes for chips on the wafer and checking adjacent chips for each chip on the wafer having a failcode to determine a failcode pattern having a defined number of chips.
摘要:
A method of analyzing cells of a memory device is disclosed. Generally, a plurality of fail signatures is generated, wherein each fail signature is associated with a type of failure. Voltages according to a plurality of test patterns are applied to nodes of a cell of the memory device. Fail data of the cell for the plurality of patterns is then analyzed, and a fail signature of the cell is determined. A type of failure of the cell based upon the plurality of fail signatures is then determined. A system for analyzing cells of a memory device is also disclosed. The system generally includes a plurality of probes applying different voltages to a cell of the memory device. A control circuit varies the voltages applied to the cell, and compares the failures of the cell as the test voltage applied to the cell is varied to an artificial bit map. Finally, an output device generates an output indicating a type of failure of the cell.
摘要:
A method of analyzing cells of a memory device is disclosed. The method generally comprises steps of establishing a plurality of fail signatures, wherein each fail signature is associated with a type of failure. Voltages according to a plurality of test patterns are applied to nodes of a cell of the memory device. Fail data of the cell for the plurality of patterns is then analyzed, and a fail signature of the cell is determined. A type of failure of the cell based upon the plurality of fail signatures is then determined. A system for analyzing cells of a memory device is also disclosed. The system preferably comprises a plurality of probes applying different voltages to a cell of the memory device. A control circuit varies the voltages applied to the cell, and compares the failures of the cell as the test voltage applied to the cell is varied to an artificial bit map. Finally, an output device generates an output indicating a type of failure of the cell.
摘要:
A method of calculating yield loss of semiconductor wafers which are tested with a test sequence to derive a total fail region count for each of the wafers, the semiconductor wafers having multiple chips thereon. The method comprises calculating a fail region count for each of the tests in the test sequence, calculating the test sequence limited yield loss for each of the wafers, and apportioning the test sequence limited yield loss to selected ones of the test based upon the absolute or cumulative number of fails identified by the tests of the test sequence. In some embodiments, core parametric test data is correlated with the test sequence limited yield and analyzed to determine reparability.
摘要:
The present invention includes a method for characterizing semiconductor failure. The method includes determining the dimensions of certain characteristics of a memory chip. The method defines a group of characteristics for a semiconductor of given dimensions. The method defines a ratio based on variables supplied by production test systems. By comparing a set of characteristics for a specific semiconductor to the ratio to determine the dominant type of failure on the semiconductor chip. The invention is an efficient method of obtaining information regarding the types of failures common on semiconductor chips.
摘要:
An IC with a memory array having a series architecture is disclosed. The memory cells of the series group are arranged in pairs in which the capacitors of a memory cell pair are stacked one on top of the other. This advantageously allows for larger capacitor arrays without increasing the chip size.
摘要:
An IC with memory cells arranged in groups is described. The memory cells, for example, are ferroelectric memory cells. The IC includes a variable voltage generator (VVG) for generating an output voltage having a different voltage level depending on a location of an addressed memory cell within the memory group is provided. By providing different voltage levels for reads and/or writes, signal loss caused by capacitances which is dependent on the location of the memory cell within the group can be avoided. This improves read and/or write operations in series memory architectures.
摘要:
A memory IC having improved sensing during reads is disclosed. The IC includes the use of first and second reference voltages for sensing to compensate for asymmetry that exists between cells on bitline true and bitline complement. The first reference voltage is used for sensing a cell on bitline true while the second reference voltage is used for sensing a cell on bitline complement.
摘要:
A method for forming uniform-depth recesses across areas of different trench density, in accordance with the present invention, includes providing a substrate having trenches formed therein. The substrate includes regions of different trench density. The trenches are filled with a first filler material, and the first filler material is removed from a surface of the substrate. A second filler material is formed over the surface of the substrate such that the depth of the second filler material is substantially uniform across the regions of different trench density. Recesses are formed in the trenches such that the recess depth below the surface of the substrate is substantially uniform across the regions
摘要:
A memory cell signal window testing apparatus 101 and method for testing the signal window of a memory are disclosed. First data is written to a memory cell during a write cycle. A low cell signal is read from the memory cell during a first read cycle. A comparison is made between the low signal and a low reference signal. The result of the comparison is stored in a first storage register. Second data is then written to the memory cell during a write cycle. A high cell signal is read from the memory cell during a second read cycle. A comparison is made between the high cell signal and a high reference signal. The result of the comparison is stored in a second storage register. The results in the first and second storage registers are compared and an output is provided indicating that the memory cell has failed the test if the comparison shows that both the low cell signal is higher than the low reference signal and the high cell signal is lower than the high reference signal.