When printed circuit board contract manufacturer Flextronics Israel ran into a high failure rate on a densely populated boards, Michael Dolkin, NPI Manager of Flextronics Israel, wasn't sure what he could do to solve the problem.

"We don't have JTAG software capability on our staff here," Mr. Dolkin said. "So we turned to StarTest to help us and they developed a test program for us that have been very successful."
The board in question was densely populated with fine-pitch integrated circuits (ICs) and ball grid arrays (BGAs). Physical access to test points and to many of the devices themselves was nonexistent. As a result, SMT's in-circuit test (ICT) equipment could not be used to locate and diagnose the problems that were causing the high failure rate.

"We use ICT equipment extensively in the tight cooperation with StarTest, but for some boards, we just don't have the access that an ICT system needs," Mr. Dolkin explained. "That's when we turn to JTAG. We use ICT and JTAG as complements to each other and that has worked very well for us. With more and more ICs having JTAG cells and the increasing density of board designs, we are turning to JTAG more often. And whenever we use JTAG, we turn to StarTest."

The JTAG test program developed and implemented by StarTest personnel using the Corelis and JTAG Tech Boundary-Scan test and in-system programming systems was able to locate many of the opens and shorts that were causing problems on the assembled boards. And when the test program could not pinpoint the exact failure, the test programs debug capability was used to troubleshoot the board until the problem was fixed.

"We don't necessarily want to develop in-house JTAG expertise, but every time we need help on a project, StarTest has come through for us. They have been very responsive and worked very hard to assure our success," Mr. Dolkin concluded.

“The design we developed was very complex. Other JTAG service providers whom we contacted found the complexity of the schematics to be a roadblock and couldn’t guarantee an acceptable fault coverage,” said Ran Salomon, Head of the ATE Group of Voltaire, that provides grid backbone solutions for networked computing in the next generation data center. “After reviewing our schematics, the StarTest DFT professionals felt they could provide the test coverage we were looking for.”

“They corrected our schematics with elimination of some redundant devices (both passive and active) and added a number of small and cheap new ones. The JTAG circuitry of our design was considerably re-built as well. Then they gave us an estimated preliminary fault test coverage report, and the percentage was already better than before. We then moved on to clustering some analog and mixed-signal devices, as well as backplane connectors, and the whole schematics fragments that was associated with the BGA’s. After a short iterative DFT analysis process and implementation of the StarTest Design-For-Testability recommendations, we were able to test pilot boards and we accomplished troubleshooting of each board within seconds. Their test program diagnostics pointed to the device and pin (or net name) in all cases. Coupled with the fault diagnostics of the JTAG structural test, the fault detection time and expenses have dropped dramatically.”

As Ran says, “I’m looking forward to having this fault coverage level in our future products too. I believe that the StarTest DFT analysis of our designs, coupled with their Boundary-Scan tests and ICT programs, will improve our yields tremendously at functional test and provide quicker feedback to the process, allowing us to eliminate manufacturing defects altogether.”

"מדיניות לביצוע בדיקות מבניות ב-Alvarion במשך שנים היא שילוב של בדיקות ICT עם בדיקות Boundary-Scan" אמר מוטי עזרא, מנהל בדיקות Alvarion. "הדרישות שלנו לאיכות בדיקה וכיסוי תקלות הן מאוד גבוהות, וזוהי הסיבה שחיפשנו קבלן משנה לעבודות האלו יסודי במיוחד, ובחרנו StarTest. אנחנו עובדים מספר שנים בצמוד עם חברה זו כקבלן משנה לפיתוח תכניות בדיקה, גם ב-ICT וגם ב-Boundary-Scan. זוהי קבוצת מומחים בעלי הבנה עמוקה בכלי פיתוח תכניות בדיקה, אנליזת תקלות וגילויין.

אנו ב-Alvarion מרוצים מאוד מהאיכות שירות בדיקות שאנו מקבלים מחברת StarTest ובכוונתנו להמשיך שיתוף פעולה פורח זו".

PMC-Sierra™ is a leading provider of broadband communications and storage semiconductors for metro, access, fiber to the home, wireless infrastructure, storage, laser printers, and fiber access gateway equipment.

Gadi Rachmani is a PMC-Sierra (Israel) Operation Manager, responsible for the boards manufacture. Gadi came to StarTest looking for a more effective method for bringing up complex prototype assemblies. The diminishing access of test points on these complex board assemblies, due to fine pitch components and restrictive packaging types such as BGA, often prevented the usage of traditional probing methods and was making board bring-up a costly and time consuming process.

Design engineers are often faced with a confounding problem when bringing up new prototype assemblies. Detecting a manufacturing defect before a design has been verified as functional can be a frustrating task. When this problem is multiplied by the inability to access crucial test points then the initial debug process can become a huge bottleneck that slips the entire development schedule. Aware of these potential pitfalls, Gadi was seeking for a more effective solution to help streamline this initial debug process.

Using the StarTest JTAG test service, PMC-Sierra (Israel) was able to create test vectors and have a test plan in place prior to receiving their first prototype boards from assembly. When the boards arrived, they connected the StarTest JTAG test equipment to their prototype boards. Before their embedded processor fetched its first opcode, they were able to execute a complete board level interconnect test, test on-board memory devices, program CPLDs and Flash memory devices, and test system logic clusters.

“The StarTest JTAG test service has been extremely helpful in getting our boards up and running. We've been able to identify manufacturing defects and have them repaired prior to trying to make the board functional. I'm sure this has saved countless troubleshooting hours. We are very pleased with the StarTest test service level and their readiness to help us immediately”, said Gadi.

כשבחברת Zicon, היצרנית כרטיסים אלקטרוניים מורכבים, קיבלו הזמנות ליצור ולהרכבת כרטיסים עם צפיפות מאוד גבוהה, מארק קריבושאי, מנהל בדיקות ב-Zicon, מתחיל לחפש קבלני משנה עם ידע ונסיון רב בתחום זה.

"לאנשי הבדיקות שלנו לא היה כל נסיון ב-JTAG, ולכן פנינו לחברת StarTest לקבלת עזרה", אומר מארק. "הם פיתחו עבורנו רצף של תכניות בדיקה במערכת Corelis, ובכך פתרו את רב בעיות הבדיקה שלנו".

מרבית הכרטיסים שמורכבים ב- Ziconהם כרטיסים צפופים מאוד עם רכיבי fine-pitch ו-BGA. הגישה הפיזית לנקודות בדיקה ולרכיבים רבים אחרים הייתה מוגבלת או לא הייתה כלל. כתוצאה מכך, אי אפשר היה להשתמש במבקדי ICT על מנת לגלות תקלות הרכבה לרכיבי SMT.

"אנו משתמשים במבדקי ICT בשיתוף פעולה הדוק עם חברת StarTest, אך למספר כרטיסים אין עדיין נקודות גישת ה-ICT הנדרשות", מסביר מארק. "זו הסיבה שבגללה פנינו לבדיקות בשיטת JTAG. אנו משלבים בדיקות JTAG עם בדיקות ICT, וזה הסיבה לקבלת התוצאות המעולות. הכרטיסים של היום מאוכלסים מאוד צפוף, ורב הרכיבים המודרניים מצוידים בתשתית JTAG, כאשר אנחנו יותר ויותר משתמשים ב-Boundary-Scan. כל פעם שאנו זקוקים לתכניות בדיקה אלו, אנו פונים ל- StarTest כמיקור חוץ".

"אנו ב- Ziconלא תכננו לגייס מומחים בטכנולוגיה זו, מכיוון שכל פעם שיש לנו צורך בתמיכה, אנו מקבלים אותה מאנשי StarTest מאופן מיידי. הם תמיד עומדים בהתחייבויותיהם ופועלים ביעילות על מנת לשמור על הצלחתנו", בזאת מסיים מארק קריבושאי מ- Zicon.