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Finite Element Based Solder Joint Fatigue Life Predictions for a Same Die Stacked Chip Scale Ball Grid Array Package Bret A. Zahn ChipPAC Inc. Abstract Viscoplastic finite-element simulation methodologies were utilized to predict solder joint reliability for a same die size, stacked, chip scale, ball grid array package under accelerated temperature cycling conditions (-40C to +125C, 15min ramps/15min dwells). The effects of multiple die attach material configurations were investigated along with the thickness of the mold cap and spacer die. The solder structures accommodate the bulk of the plastic strain that is generated during accelerated temperature cycling due to the thermal expansion mismatch between the various materials that encompass the stacked die package. Since plastic strain is a dominant parameter that influences low-cycle fatigue, it was used as a basis for evaluation of solder joint structural integrity. The paper discusses the analysis methodologies as implemented in the ANSYS finite element simulation software tool and the corresponding results for the solder joint fatigue life. Some ANSYS parametric design language commands are included for the benefit of those readers who are familiar with the tool. Introduction As the demand for more functionality in electronic systems continues to grow, more effort is focused on the development of system-in-a-chip devices. For years, the least expensive way to add more functions to an electronic system was to integrate more functions into the individual chips themselves. However, cost and yield issues can prevent such integration from being economically feasible. Furthermore, some chip sets that logically belong together to form a system or subsystem cannot be integrated into a single die due to differences in the die materials. Such is the case with silicon and gallium arsenide. High-density packaging technologies have advanced to the point where intentionally splitting a single chip system into multiple dice can provide both performance and cost advantages. System-in-a-package solutions are expected to grow significantly in market share, offering a favorable combination of cost, speed, and density. One classification of a system-in-a-package solution gaining wider acceptance is the stacked-die package, where the main concern is saving space. It is feasible that in such a package, the stacked die may be of the same size, thus requiring the insertion of a spacer between the two active die in order to facilitate wire bonding to each of the die surfaces. The solder joint fatigue reliability concerns of such a package are analyzed herein under accelerated temperature cycling conditions (-40C to +125C, 15min ramps/15min dwells). Such conditions are commonly evaluated as part of the package qualification process. The integrity of solder joints is a major reliability concern in modern microelectronic packages. Temperature fluctuations caused by either power transients or environmental changes, along with the resulting thermal expansion mismatch between the various package materials, results in time and temperature dependent creep deformation of solder. This deformation accumulates with repeated cycling and ultimately causes solder joint cracking and interconnect failure. To minimize development costs and maximize reliability performance, advanced analysis is a necessity during the design and development phase of a microelectronic package. This requires the utilization of a life prediction methodology that is based on the damage mechanisms experienced in a field operation environment. Several finite element based analysis methodologies have been proposed which predict solder joint fatigue life (e.g. Engelmaier [1]; Shine and Fox [2]; Wong et al. [3]; Yamada [4]; Subrahmanyan et al. [5]; Dasgupta et al. [6]; Pao [7]; Clech et al. [8]; Syed [9]; Darveaux et al. [10]; and Darveaux [11]). It should be noted that there is a material limitation inherent to many of these methodologies since they assume the utilization of eutectic 63Sn/37Pb solder or some similar combination of solder materials (i.e.

Soalan-soalan Lazim Peneraju Skil Juruteknik Pesawat Berlesen

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Page 1: Soalan-soalan Lazim Peneraju Skil Juruteknik Pesawat Berlesen

Soalan-soalan Lazim

Peneraju Skil Juruteknik Pesawat Berlesen (upgradable to Peneraju Profesional Jurutera Pesawat Berlesen)

A. PROGRAMME OVERVIEW

1. What is the programme about? What does it aim to achieve?

The Peneraju Skil Juruteknik Pesawat Berlesen programme is an initiative that was launched in

2013; to meet the increasing needs of the aviation industry of licensed MRO (Maintenance, Repair

& Overhaul) professionals.

This initiative is intended to increase the numbers of Bumiputera MRO professionals to support the

growing MRO industry. This is in line with Yayasan Peneraju’s main objective to optimize

Bumiputera capabilities towards high income employment through quality education and

certifications.

2. Why do you call this programme ‘upgradable’ to Peneraju Profesional Jurutera Pesawat

Berlesen?

This MRO programme is a performance-based programme. It is possible for a ‘Juruteknik’ to get

promoted to ‘Jurutera’ and vice versa; where a ‘Jurutera’ maybe demoted to ‘Juruteknik’. Yayasan

Peneraju is streamlining the intake to begin at ‘Juruteknik’ level first and all candidates need to earn

their promotion to ‘Jurutera’

3. How long is the Peneraju Skil Juruteknik Pesawat Berlesen programme?

The Peneraju Skil Juruteknik Pesawat Berlesen is a 3 – 5 year programme based on the stream after

the first year of review. For ‘Juruteknik’ it will take 3 years and for ‘Jurutera’, it will take 5 years.

4. Is the Peneraju Skil Juruteknik Pesawat Berlesen programme a scholarship or a study loan?

The Peneraju Skil Juruteknik Pesawat Berlesen is a sponsorship programme. Scholars are only

required to pay a maximum of 20% of the overall programme cost; terms and conditions apply.

Programme costs include training fees, exam fees, Assessment fees, accommodation,

transportation and scholars’ subsistence. Repayment of the 20% will only take effect after the

completion of training. Further reduction in amount to pay will be subjected to Yayasan Peneraju’s

discretion and scholar performance.

5. Am I right the candidate for this programme?

This programme is opened to Bumiputera not more than 28 years old on closing date of application

with minimum SPM Grade ‘C’ in English, Bahasa Malaysia, Physics and Mathematics; and do not

suffer from chronic asthma and is not colour blind.

Page 2: Soalan-soalan Lazim Peneraju Skil Juruteknik Pesawat Berlesen

6. How can I apply for this programme?

Interested applicants may start to register their interest through the Online Form available on

Yayasan’s website at www.yayasanpeneraju.com.my

The application opens from 25 February 2016.

Shortlisted applicants will be contacted to attend the assessment sessions on selected dates in

December. During the assessment sessions; candidates will be assessed (examination-based:

English and Mechanical Reasoning) and interviewed.

Successful candidates will start the programme in two intakes, June and September 2016.

7. What are the benefits for the recipients of the Peneraju Skil Juruteknik Pesawat Berlesen

programme and how is it different from other programmes?

This programme provides you the opportunity to obtain PART 66 Category A (Technician) or

Category B1 (Engineer) license at an accredited leading MRO training provider in Malaysia (Part 147

by Department of Civil Aviation Malaysia)

The classes are conducted by experienced MRO instructors/practitioners from the industry

supplemented by development programmes which help with scholars’ soft skills, personal

advancement and industry insights. Successful scholars will also be offered job placements in the

industry.

Intensive English classes will also be provided.

B. APPLICATION

1. How would I know if my application has been shortlisted for the written assessment stage?

Only shortlisted applicants will be notified to attend the written assessment.

2. What if I’m currently working? Do I need to resign from my current employment if I wish to

undertake the Peneraju Skil Juruteknik Pesawat Berlesen programme?

Yes. This is a full-time programme, which requires scholars to be in training 5 to 7 days a week and

live in a dormitory environment.

3. If I receive another loan/scholarship, am I still eligible to receive Yayasan Peneraju’s

sponsorship?

No. Only one sponsorship is allowed at one time.

C. OTHER DETAILS

Page 3: Soalan-soalan Lazim Peneraju Skil Juruteknik Pesawat Berlesen

1. Would I be bonded with Yayasan Peneraju after I have finished the programme? If yes, how

many years would the bond be in effect?

No. Scholars who have completed the programme will not be bonded by Yayasan Peneraju. The

Peneraju Skil Juruteknik Pesawat Berlesen is a 3 -5 year programme; and scholars are only required

to complete / acquire the license at the end of the 3/5 years.

However, scholars are required to work in the industry for 3 years (Technician) and 5 years

(Engineer) after obtaining license.

2. How many scholarships are Yayasan Peneraju offering for the Peneraju Skil Juruteknik Pesawat

Berlesen for the year 2016?

Yayasan Peneraju is offering 100 scholarships every year for the Peneraju Skil Juruteknik Pesawat

Berlesen programme. However the final number of scholarships that will be offered is subject to

the quality and calibre of the qualified candidates’ pool we receive each year.

3. Am I required to commit to any kind of official contract/ agreement?

Yes. A contract will be established. 4. Would I be able to reject the Peneraju Skil Juruteknik Pesawat Berlesen offer if I am shortlisted? Yes. Contract is only bound after Letter of Offer to the candidate is accepted, signed and delivered to Yayasan Peneraju. 5. What are the consequences I face, should the contract is breached? Scholars who withdraw from the programme are required to pay all costs incurred up to the point of breach to Yayasan Peneraju.