Predicting thermomechanical stress using MESMERIC methodology

O. Slattery; D. O'Mahoney; E. Sheehan; F. Waldron; G. McCarthy

doi:10.1109/ITHERM.2002.1012548

Predicting thermomechanical stress using MESMERIC methodology

O. Slattery, D. O'Mahoney, E. Sheehan, F. Waldron, G. McCarthy

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

Packaged ICs are subjected to thermomechanical stress during manufacture and operation. Accurate characterisation of these stresses, which may induce failure, is complex and is the subject of the work in this paper. This paper firstly describes a methodology for predicting thermomechanical stress in packaged die. A novel test chip with piezoresistive strain gauges is designed to allow detailed mapping of the stress distribution on the die surface. Two measurement techniques were developed for characterisation of the strain gauges. A vacuum test fixture allows characterisation of the gauges at wafer level and a four point bending fixture was developed for measurement of wafer strips. 3D finite element techniques were used to simulate the stresses on the samples in the measurement fixtures. Simulated stresses were used in conjunction with resistance changes measured in the fixtures to calculate the piezoresistive coefficients for the strain gauges. Secondly, this paper investigates one of the most commonly used assumptions in finite element modelling of encapsulation induced stresses, namely that all package materials are stress free at encapsulation temperature. Simulated results are compared with measured package warpage and the results indicate that package warpage may be overpredicted using this assumption.

Original language	English
Title of host publication	ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems
Editors	Bahgat G. Sammakia, Yogendra K. Joshi, Ganesh Subbarayan, Cristina H. Amon, Koneru Ramakrishna, Sanjeev B. Sathe
Publisher	IEEE Computer Society
Pages	884-891
Number of pages	8
ISBN (Electronic)	0780371526
DOIs	https://doi.org/10.1109/ITHERM.2002.1012548
Publication status	Published - 2002
Externally published	Yes
Event	8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM 2002 - San Diego, United States Duration: 30 May 2002 → 1 Jun 2002

Publication series

Name	InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM
Volume	2002-January
ISSN (Print)	1936-3958

Conference

Conference	8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM 2002
Country/Territory	United States
City	San Diego
Period	30/05/02 → 1/06/02

Keywords

Electrical resistance measurement
Finite element methods
Fixtures
Packaging
Piezoresistance
Strain measurement
Stress measurement
Testing
Thermal stresses
Thermomechanical processes

Access to Document

10.1109/ITHERM.2002.1012548

Cite this

Slattery, O., O'Mahoney, D., Sheehan, E., Waldron, F., & McCarthy, G. (2002). Predicting thermomechanical stress using MESMERIC methodology. In B. G. Sammakia, Y. K. Joshi, G. Subbarayan, C. H. Amon, K. Ramakrishna, & S. B. Sathe (Eds.), ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (pp. 884-891). Article 1012548 (InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM; Vol. 2002-January). IEEE Computer Society. https://doi.org/10.1109/ITHERM.2002.1012548

Slattery, O. ; O'Mahoney, D. ; Sheehan, E. et al. / Predicting thermomechanical stress using MESMERIC methodology. ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems. editor / Bahgat G. Sammakia ; Yogendra K. Joshi ; Ganesh Subbarayan ; Cristina H. Amon ; Koneru Ramakrishna ; Sanjeev B. Sathe. IEEE Computer Society, 2002. pp. 884-891 (InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM).

@inproceedings{d0c534ecf16841e58080c3e090a668dc,

title = "Predicting thermomechanical stress using MESMERIC methodology",

abstract = "Packaged ICs are subjected to thermomechanical stress during manufacture and operation. Accurate characterisation of these stresses, which may induce failure, is complex and is the subject of the work in this paper. This paper firstly describes a methodology for predicting thermomechanical stress in packaged die. A novel test chip with piezoresistive strain gauges is designed to allow detailed mapping of the stress distribution on the die surface. Two measurement techniques were developed for characterisation of the strain gauges. A vacuum test fixture allows characterisation of the gauges at wafer level and a four point bending fixture was developed for measurement of wafer strips. 3D finite element techniques were used to simulate the stresses on the samples in the measurement fixtures. Simulated stresses were used in conjunction with resistance changes measured in the fixtures to calculate the piezoresistive coefficients for the strain gauges. Secondly, this paper investigates one of the most commonly used assumptions in finite element modelling of encapsulation induced stresses, namely that all package materials are stress free at encapsulation temperature. Simulated results are compared with measured package warpage and the results indicate that package warpage may be overpredicted using this assumption.",

keywords = "Electrical resistance measurement, Finite element methods, Fixtures, Packaging, Piezoresistance, Strain measurement, Stress measurement, Testing, Thermal stresses, Thermomechanical processes",

author = "O. Slattery and D. O'Mahoney and E. Sheehan and F. Waldron and G. McCarthy",

note = "Publisher Copyright: {\textcopyright} 2002 IEEE.; 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM 2002 ; Conference date: 30-05-2002 Through 01-06-2002",

year = "2002",

doi = "10.1109/ITHERM.2002.1012548",

language = "English",

series = "InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM",

publisher = "IEEE Computer Society",

pages = "884--891",

editor = "Sammakia, {Bahgat G.} and Joshi, {Yogendra K.} and Ganesh Subbarayan and Amon, {Cristina H.} and Koneru Ramakrishna and Sathe, {Sanjeev B.}",

booktitle = "ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems",

}

Slattery, O, O'Mahoney, D, Sheehan, E, Waldron, F & McCarthy, G 2002, Predicting thermomechanical stress using MESMERIC methodology. in BG Sammakia, YK Joshi, G Subbarayan, CH Amon, K Ramakrishna & SB Sathe (eds), ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems., 1012548, InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM, vol. 2002-January, IEEE Computer Society, pp. 884-891, 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM 2002, San Diego, United States, 30/05/02. https://doi.org/10.1109/ITHERM.2002.1012548

Predicting thermomechanical stress using MESMERIC methodology. / Slattery, O.; O'Mahoney, D.; Sheehan, E. et al.
ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems. ed. / Bahgat G. Sammakia; Yogendra K. Joshi; Ganesh Subbarayan; Cristina H. Amon; Koneru Ramakrishna; Sanjeev B. Sathe. IEEE Computer Society, 2002. p. 884-891 1012548 (InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM; Vol. 2002-January).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

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N2 - Packaged ICs are subjected to thermomechanical stress during manufacture and operation. Accurate characterisation of these stresses, which may induce failure, is complex and is the subject of the work in this paper. This paper firstly describes a methodology for predicting thermomechanical stress in packaged die. A novel test chip with piezoresistive strain gauges is designed to allow detailed mapping of the stress distribution on the die surface. Two measurement techniques were developed for characterisation of the strain gauges. A vacuum test fixture allows characterisation of the gauges at wafer level and a four point bending fixture was developed for measurement of wafer strips. 3D finite element techniques were used to simulate the stresses on the samples in the measurement fixtures. Simulated stresses were used in conjunction with resistance changes measured in the fixtures to calculate the piezoresistive coefficients for the strain gauges. Secondly, this paper investigates one of the most commonly used assumptions in finite element modelling of encapsulation induced stresses, namely that all package materials are stress free at encapsulation temperature. Simulated results are compared with measured package warpage and the results indicate that package warpage may be overpredicted using this assumption.

AB - Packaged ICs are subjected to thermomechanical stress during manufacture and operation. Accurate characterisation of these stresses, which may induce failure, is complex and is the subject of the work in this paper. This paper firstly describes a methodology for predicting thermomechanical stress in packaged die. A novel test chip with piezoresistive strain gauges is designed to allow detailed mapping of the stress distribution on the die surface. Two measurement techniques were developed for characterisation of the strain gauges. A vacuum test fixture allows characterisation of the gauges at wafer level and a four point bending fixture was developed for measurement of wafer strips. 3D finite element techniques were used to simulate the stresses on the samples in the measurement fixtures. Simulated stresses were used in conjunction with resistance changes measured in the fixtures to calculate the piezoresistive coefficients for the strain gauges. Secondly, this paper investigates one of the most commonly used assumptions in finite element modelling of encapsulation induced stresses, namely that all package materials are stress free at encapsulation temperature. Simulated results are compared with measured package warpage and the results indicate that package warpage may be overpredicted using this assumption.

KW - Electrical resistance measurement

KW - Finite element methods

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KW - Piezoresistance

KW - Strain measurement

KW - Stress measurement

KW - Testing

KW - Thermal stresses

KW - Thermomechanical processes

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Slattery O, O'Mahoney D, Sheehan E, Waldron F, McCarthy G. Predicting thermomechanical stress using MESMERIC methodology. In Sammakia BG, Joshi YK, Subbarayan G, Amon CH, Ramakrishna K, Sathe SB, editors, ITHERM 2002 - 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems. IEEE Computer Society. 2002. p. 884-891. 1012548. (InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM). doi: 10.1109/ITHERM.2002.1012548

Predicting thermomechanical stress using MESMERIC methodology

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