Study on fab environment induced Al and Cu metal corrosion by TEM failure analysis

2005 ◽

Author(s):

John Butchko ◽

Bruce T. Gillette

Keyword(s):

Corrosion Rate ◽

Grain Boundary ◽

Failure Analysis ◽

Failure Mechanism ◽

Metal Corrosion ◽

Corrosion Mechanism ◽

Reliability Testing ◽

Process Change ◽

Transistor Reliability ◽

Pass Through

Abstract Autoclave Stress failures were encountered at the 96 hour read during transistor reliability testing. A unique metal corrosion mechanism was found during the failure analysis, which was creating a contamination path to the drain source junction, resulting in high Idss and Igss leakage. The Al(Si) top metal was oxidizing along the grain boundaries at a faster rate than at the surface. There was subsurface blistering of the Al(Si), along with the grain boundary corrosion. This blistering was creating a contamination path from the package to the Si surface. Several variations in the metal stack were evaluated to better understand the cause of the failures and to provide a process solution. The prevention of intergranular metal corrosion and subsurface blistering during autoclave testing required a materials change from Al(Si) to Al(Si)(Cu). This change resulted in a reduced corrosion rate and consequently prevented Si contamination due to blistering. The process change resulted in a successful pass through the autoclave testing.

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Case study: Failure analysis for metal corrosion induced by pressure pot test

Microelectronics Reliability ◽

10.1016/j.microrel.2010.07.098 ◽

2010 ◽

Vol 50 (9-11) ◽

pp. 1436-1440

Author(s):

D. Mello ◽

R. Ricciari ◽

M. Aiello ◽

M. Astuto

Keyword(s):

Failure Analysis ◽

Metal Corrosion

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Failure Analysis and Elimination of Galvanic Corrosion on Bondpads During Wafer Sawing

ISTFA 2000: Conference Proceedings from the 26th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2000p0369 ◽

2000 ◽

Author(s):

Y. N. Hua ◽

E. C. Low ◽

L. H. An ◽

Shailesh Redkar

Keyword(s):

Failure Analysis ◽

Feed Rate ◽

Galvanic Corrosion ◽

Experimental Results ◽

Metal Corrosion ◽

Wafer Fabrication ◽

Al Alloy ◽

Assembly Process ◽

Water Problem ◽

Sawing Process

Abstract In our previous paper [1], discolored bondpads due to galvanic corrosion were studied. The results showed that the galvanic corrosion occurred in 0.8 ìm wafer fabrication (fab) process with cold Al alloy (Al-Si, 0.8 wt%-Cu, 0.5 wt%) metallization. Galvanic corrosion is also known as a two-metal corrosion and it could be due to either wafer fab process or assembly process. Our initial suspicion was that it was due to a DI water problem during wafer sawing at assembly process. After that, we did further failure analysis and investigation work on galvanic corrosion of bondpads and further found that galvanic corrosion might be due to longer rinsing time of DI water during wafer sawing. The rinsing time of DI water is related to the cutting time of wafer sawing. Therefore, some experiments of wafer sawing process were done by using different sizes of wafer (1/8 of wafer, a quadrant of wafer and whole of wafer) and different sawing speed (feed-rate). The results showed that if the cutting time was longer than 25 minutes, galvanic corrosion occurred on bondpads. However, if the cutting time was shorter than 25 minutes, galvanic corrosion was eliminated. Based on the experimental results, it is concluded that in order to prevent galvanic corrosion of bondpads, it is necessary to select higher feed-rate during wafer sawing process at assembly houses. In this paper, we will report the details of failure analysis and simulation experimental results, including the solution to eliminate galvanic corrosion of bondpads during wafer sawing at assembly houses.

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Failure Analysis With the Scanning Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095662 ◽

1972 ◽

Vol 30 ◽

pp. 482-483

Author(s):

John R. Devaney

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Integrated Circuits ◽

Failure Analysis ◽

High Reliability ◽

Military Applications ◽

Small Structure ◽

Useful Life ◽

Insight Into ◽

Scanning Electron

Occasionally in history, an event may occur which has a profound influence on a technology. Such an event occurred when the scanning electron microscope became commercially available to industry in the mid 60's. Semiconductors were being increasingly used in high-reliability space and military applications both because of their small volume but, also, because of their inherent reliability. However, they did fail, both early in life and sometimes in middle or old age. Why they failed and how to prevent failure or prolong “useful life” was a worry which resulted in a blossoming of sophisticated failure analysis laboratories across the country. By 1966, the ability to build small structure integrated circuits was forging well ahead of techniques available to dissect and analyze these same failures. The arrival of the scanning electron microscope gave these analysts a new insight into failure mechanisms.

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Using the scanning electron microscope for failure analysis of high density magnetic media

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126755 ◽

1987 ◽

Vol 45 ◽

pp. 392-393

Author(s):

Evelyn R. Ackerman ◽

Gary D. Burnett

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Failure Analysis ◽

High Density ◽

Magnetic Media ◽

Specific Data ◽

Retrieval Systems ◽

Operating Environments ◽

The Media ◽

Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

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