Failure analysis and testing of semi-conductor devices using intelligent software on automated test equipment (ATE)
AssigneeLSI Logic Corporation
InventorRoger Yacobucci
Life of this patent
Estimating the term…
Abstract
The invention provides a number of related methods which improve the test and analysis of integrated circuit devices. A first method of the invention provides a method for pausing on a SCAN based test. A second method of the invention provides a method for using stimulations and responses of a known good device to increase fault coverage of patterns in a test flow. A third method of the invention provides a method to curve trace device buffers on an ATE.
Claims16
A method for pausing on a SCAN based test, said method comprising the steps of:
- a) reading original SCAN chain data for a SCAN partition;
- b) saving said original SCAN chain data;
- c) rewriting said original SCAN chain data with a strobe character at a link in said original SCAN chain data where a pause is desired;
- d) setting a compare level for an output pin associated with said strobe character so that a device under test failure results when automatic test equipment executes said SCAN partition;
- e) masking all output pins except for said output pin associated with said strobe character;
- f) executing said SCAN partition to failure in order to provide a paused condition;
- g) performing any desired tasks during said paused condition;
- h) if a paused condition is necessary on another link in said original SCAN chain data, returning to step (c) of said method, otherwise moving forward to step (i);
- and
- i) rewriting said original SCAN chain data back to said automatic test equipment which was saved in step (b).
A method for using stimulations and responses of a known good device to increase fault coverage of patterns in a test flow, said method comprising the steps of:
- a) pausing on one of said patterns in said test flow;
- b) providing an appropriate computer program;
- c) having said appropriate computer program query a user regarding a plurality of items;
- d) having said appropriate computer program start processing one inspect vector within an inspect vector range by characterizing each signal on said inspect vector with non-strobed characters to determine whether an output signal is being driven;
- e) if said output signal is being driven, having said appropriate computer program change said non-strobed character to a high or low strobe character to provide a new vector, depending on whether said output signal is an output that is being driven to a high or low state;
- f) running said pattern with said new vector for consecutive passes required at both minimum and maximum VDD device power settings to insure said new vector is not marginal.
- g) if any of said high or low strobe characters fail during consecutive passes at said minimum and maximum VDD device power settings, resetting said high or low strobe characters back to said non-strobed characters and retesting;
- and
- h) repeating steps (d) through (g) as necessary.
A method to curve trace device buffers on an ATE, said method comprising the steps of:
- a) defining a predetermined pin list which is set to include all pins during pattern loads;
- b) modifying said predetermined pin list using a predetermined debugger command in order to include desired pins for characterization using an appropriate computer program;
- c) having said appropriate computer program query a user regarding a plurality of items;
- d) reading one of said pins from said predetermined pin list;
- e) using pin measurement units to force incrementally increasing voltage from zero volts until a predefined maximum current limit is reached;
- f) flagging any problem pins identified in step (e) and storing values at each increment to data files;
- g) using pin measurement units to force incrementally decreasing voltage from zero to a predefined minimum current limit is reached;
- h) flagging any problem pins identified in step (g) and storing values at each increment to data files;
- and
- i) if all of said pins in said predetermined pin list have not been evaluated, returning to step (d).
Dependencies are inferred from the claim text.