Materials-based failure analysis in design of electronic devices, and prediction of operating life

• US 20080015827A1
• Filed: 03/13/2007
• Published: 01/17/2008
• Est. Priority Date: 01/24/2006
• Status: Active Grant

• Current Assignee: Vextec Corporation
• Original Assignee: Vextec Corporation
• Inventors: Tryon, Robert, Nasser, Loren, Krishnan, Ganapathi, Dey, Animesh
• Granted Patent: US 8,290,753 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA

Abstract

The technology includes for methods, a system, and a computer readable medium for modeling the failure of an electronic component, based on a detailed simulation of fatigue mechanisms in the component. The technology further includes methods, system, and a medium programmed to predict failure of a system that includes an electronic component, based on modeling one or more fatigue mechanisms in the component.

Claims

1. A method of predicting time to failure of an electronic component, the method comprising:

generating a finite element model of the component, wherein the finite element model comprises a plurality of nodes, and wherein a value of at least one stress variable is associated with each node of the plurality of nodes;

defining at least one representative volume element for each node of the plurality of nodes whose value of at least one stress variable exceeds a threshold;

developing a microstructure-based failure model for each of the representative volume elements, wherein the microstructure-based failure model uses random initial values for one or more properties of the microstructure, and wherein the microstructure-based failure model comprises one or more cyclic fatigue models selected from the group consisting of crack nucleation, short crack growth, and long crack growth models, and further comprises one or more time-dependent fatigue models selected from the group consisting of crack nucleation, short crack growth, and long crack growth models;

simulating failure of each node by applying the value of the at least one stress variable for that node to the microstructure-based failure model for each of the representative volume elements for that node, thereby calculating a predicted time to failure for each representative volume element; and

calculating a time to failure for the component by choosing the shortest predicted time to failure for any node.

2. The method of claim 1, further comprising:

performing the simulating of failure for each node a plurality of times, using different initial values for the one or more properties of the microstructure, thereby producing a plurality of predicted times to failure for the component; and

deriving a probabilistic model of failure of the component based on the plurality of predicted times to failure.

3. A computer system, configured to predict time to failure of an electronic component, the system comprising:

a memory; and

a processor, wherein the processor is configured to execute instructions for;

generating a finite element model of the component, wherein the finite element model comprises a plurality of nodes, and wherein a value of at least one stress variable is associated with each node of the plurality of nodes;

defining at least one representative volume element for each node of the plurality of nodes whose value of at least one stress variable exceeds a threshold;

developing a microstructure-based failure model for each of the representative volume elements, wherein the microstructure-based failure model uses random initial values for one or more properties of the microstructure, and wherein the microstructure-based failure model comprises one or more cyclic fatigue models selected from the group consisting of crack nucleation, short crack growth, and long crack growth models, and further comprises one or more time-dependent fatigue models selected from the group consisting of crack nucleation, short crack growth, and long crack growth models;

simulating failure of each node by applying the value of the at least one stress variable for that node to the microstructure-based failure model for each of the representative volume elements for that node, thereby calculating a predicted time to failure for each representative volume element; and

calculating a time to failure for the component by choosing the shortest predicted time to failure for any node.

4. The system of claim 3, wherein the processor is further configured to execute instructions comprising:

performing the simulating of failure for each node a plurality of times, using different initial values for the one or more properties of the microstructure, thereby producing a plurality of predicted times to failure for the component; and

deriving a probabilistic model of failure of the component based on the plurality of predicted times to failure.

5. A computer readable medium, configured with instructions to predict time to failure of an electronic component, the instructions comprising instructions for:

generating a finite element model of the component, wherein the finite element model comprises a plurality of nodes, and wherein a value of at least one stress variable is associated with each node of the plurality of nodes;

defining at least one representative volume element for each node of the plurality of nodes whose value of at least one stress variable exceeds a threshold;

developing a microstructure-based failure model for each of the representative volume elements, wherein the microstructure-based failure model uses random initial values for one or more properties of the microstructure, and wherein the microstructure-based failure model comprises one or more cyclic fatigue models selected from the group consisting of crack nucleation, short crack growth, and long crack growth models, and further comprises one or more time-dependent fatigue models selected from the group consisting of crack nucleation, short crack growth, and long crack growth models;

simulating failure of each node by applying the value of the at least one stress variable for that node to the microstructure-based failure model for each of the representative volume elements for that node, thereby calculating a predicted time to failure for each representative volume element; and

calculating a time to failure for the component by choosing the shortest predicted time to failure for any node.

6. The computer readable medium of claim 5, wherein the medium is further encode with instructions to:

perform the simulating of failure for each node a plurality of times, using different initial values for the one or more properties of the microstructure, thereby producing a plurality of predicted times to failure for the component; and

derive a probabilistic model of failure of the component based on the plurality of predicted times to failure.