Studies on Fingerprints of EDX, FTIR, XPS and TOF-SIMS Techniques and Applications in Failure Analysis of Wafer Fabrication

Author(s):  
Hua Younan ◽  
Lo Keng Foo ◽  
N. Ramesh Rao ◽  
Z. Q. Mo

Abstract In failure analysis of wafer fabrication it is difficult to identify possible sources of carbon-related contaminants as most of them are from polymers, organic and complex compounds. In this paper, the fingerprints of EDX, FTIR, XPS and TOFSIMS techniques will be introduced so as to identify sources of carbon-related contaminants. For example, Si peak (1.740 keV) can be used as a fingerprint of EDX technique to identify the ink-related contaminant from the other carbon-related contaminants. FTIR spectra of more than 10 possible materials from wafer fab and assembly processes are discussed, which may be used as the fingerprints of FTIR technique to identify carbon-related contaminants. The C=O functional group and the PDMS (PolyDimethylSiloxane) are recommended as the fingerprints of XPS and TOF-SIMS techniques to identify source of carbon-related contaminants, respectively. In this paper, some application cases will be also discussed.

Author(s):  
Hua Younan

Abstract A failure analysis flow is developed for surface contamination, corrosion and underetch on microchip Al bondpads and it is applied in wafer fabrication. SEM, EDX, Auger, FTIR, XPS and TOF-SIMS are used to identify the root causes. The results from carbon related contamination, galvanic corrosion, fluorine-induced corrosion, passivation underetch and Auger bondpad monitoring will be presented. The failure analysis flow will definitely help us to select suitable methods and tools for failure analysis of Al bondpad-related issues, identify rapidly possible root causes of the failures and find the eliminating solutions at both wafer fabrication and assembly houses.


Author(s):  
Younan N. Hua

Abstract Discolored bondpads & non-stick failure in 0.6 μm wafer fab process with the hot Al alloy metallization was investigated. SEM, EDX & AES techniques were used to identify the root causes. Failure analysis results showed that discolored bondpads & non-stick failure were caused by TiN residue introduced during L95 bondpad opening wafer fab process. TiN residue on bondpad might have led to non-stick bondpad issue. The results also showed that it was difficult to determine the trace amount of TiN residue on bondpad using EDX technique due to its limitations. In this work, Auger surface analysis technique was used to determine TiN residue on bondpads with Al/TiW/Ti metallization. Auger results showed that Ti & N peaks were detected on discolored bondpads. It has resulted in non-stick bondpad failure. The solution to eliminate TiN residue on bondpads was to increase etch time at L95 bondpad opening wafer fab process. After using the new recipe with longer etch time, Auger results on the bondpads showed that no Ti & N peaks were detected and the bond-pull testing also passed.


Author(s):  
Hua Younan ◽  
Chu Susan ◽  
Gui Dong ◽  
Mo Zhiqiang ◽  
Xing Zhenxiang ◽  
...  

Abstract As device feature size continues to shrink, the reducing gate oxide thickness puts more stringent requirements on gate dielectric quality in terms of defect density and contamination concentration. As a result, analyzing gate oxide integrity and dielectric breakdown failures during wafer fabrication becomes more difficult. Using a traditional FA flow and methods some defects were observed after electrical fault isolation using emission microscopic tools such as EMMI and TIVA. Even with some success with conventional FA the root cause was unclear. In this paper, we will propose an analysis flow for GOI failures to improve FA’s success rate. In this new proposed flow both a chemical method, Wright Etch, and SIMS analysis techniques are employed to identify root cause of the GOI failures after EFA fault isolation. In general, the shape of the defect might provide information as to the root cause of the GOI failure, whether related to PID or contamination. However, Wright Etch results are inadequate to answer the questions of whether the failure is caused by contamination or not. If there is a contaminate another technique is required to determine what the contaminant is and where it comes from. If the failure is confirmed to be due to contamination, SIMS is used to further determine the contamination source at the ppm-ppb level. In this paper, a real case of GOI failure will be discussed and presented. Using the new failure analysis flow, the root cause was identified to be iron contamination introduced from a worn out part made of stainless steel.


Author(s):  
Oliver D. Patterson ◽  
Deborah A. Ryan ◽  
Xiaohu Tang ◽  
Shuen Cheng Lei

Abstract In-line E-beam inspection may be used for rapid generation of failure analysis (FA) results for low yielding test structures. This approach provides a number of advantages: 1) It is much earlier than traditional FA, 2) de-processing isn’t required, and 3) a high volume of sites can be processed with the additional support of an in-line FIB. Both physical defect detection and voltage contrast inspection modes are useful for this application. Voltage contrast mode is necessary for isolation of buried defects and is the preferred approach for opens, because it is faster. Physical defect detection mode is generally necessary to locate shorts. The considerations in applying these inspection modes for rapid failure analysis are discussed in the context of two examples: one that lends itself to physical defect inspection and the other, more appropriately addressed with voltage contrast inspection.


Author(s):  
Y. N. Hua ◽  
Z. R. Guo ◽  
L. H. An ◽  
Shailesh Redkar

Abstract In this paper, some low yield cases in Flat ROM device (0.45 and 0.6 µm) were investigated. To find killer defects and particle contamination, KLA, bitmap and emission microscopy techniques were used in fault isolation. Reactive ion etching (RIE) and chemical delayering, 155 Wright Etch, BN+ Etch and scanning electron microscope (SEM) were used for identification and inspection of defects. In addition, energy-dispersive X-ray microanalysis (EDX) was used to determine the composition of the particle or contamination. During failure analysis, seven kinds of killer defects and three killer particles were found in Flat ROM devices. The possible root causes, mechanisms and elimination solutions of these killer defects/particles were also discussed.


Author(s):  
P. Egger ◽  
C. Burmer

Abstract The area of embedded SRAMs in advanced logic ICs is increasing more and more. On the other hand smaller structure sizes and an increasing number of metal layers make conventional failure localization by using emission microscopy or liquid crystal inefficient. In this paper a SRAM failure analysis strategy will be presented independent on layout and technology.


Author(s):  
Abigail A. Enders ◽  
Nicole M. North ◽  
Chase M. Fensore ◽  
Juan Velez-Alvarez ◽  
Heather C. Allen

2003 ◽  
Vol 56 (9) ◽  
pp. 903 ◽  
Author(s):  
Gavin E. Collis ◽  
Dieter Wege

Addition of 2-diazopropane to 1,4-naphthoquinone at low temperature, followed by in situ enolization and acetylation or silylation gave 3,3-dimethyl-1H-benz[f]indazol-4,9-diyl diacetate and 3,3-dimethyl-9-(t-butyl-dimethylsilyloxy)-1H-benz[f]indazol-4-ol, respectively. Functional group manipulation of the latter compound provided a number of other 4,9-disubstituted 3,3-dimethyl-3H-benz[f]indazoles. Irradiation of the diacetate led to clean extrusion of nitrogen to give the naphtho[b]cycloproparene and an alkene. Attempts to elaborate the cycloproparene into the derived cyclopropanaphthoquinone were unsuccessful. Of the other 4,9-disubstituted 3,3-dimethyl-3H-benz[f]indazoles examined, only the compound possessing an acetoxy group at C9 was photoactive, and afforded the expected cycloproparene and alkene. Compounds bearing a hydroxy or alkoxy group at C9 were photochemically inert.


2020 ◽  
Vol 25 (2) ◽  
pp. 71
Author(s):  
Dwi Ajias Pramasari ◽  
Dewi Sondari ◽  
Danang Sudarwoko Adi ◽  
Bernadeta Ayu Widyaningrum ◽  
Anugerah Fajar ◽  
...  

Microporous starch can be used as oil adsorbent agent. The microporous starch can be produced through partial hydrolysis at temperature below gelatinization point using amylase. On the other hand, the study of amylase produced from Indonesian sea microbe, especially Brevibacterium sp. was rarely studied. Therefore, this paper discusses the tapioca characteristic made from Brevibacterium sp. amylase (treatment A) and commercial amylase (treatment B) as oil adsorbent agent. The result showed that the yield from treatment A and B was 74.65% and 12.75% while the starch granule size was 14.60 μm and 12,59 μm. The adsorbent test showed adsorption level of oil palm were 91,08% and 142,14% while for olive oil were 94,70% and 133,17%, for treatment A and B, respectively. The morphological test showed the presence of pori on the granule surface for both treatments with FTIR assessment showed no significant change in chemical functional group for both treatments. The color analysis showed almost similar brightness level between two treatments. In the end, microporous starch of treatment A has prospect as oil adsorbent agent like the one from commercial amylase


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