A novel low temperature bonding technique for plastic substrates using X-ray irradiation

Author(s):  
Hyun Sup Lee ◽  
Dong Sung Kim ◽  
Tai Hun Kwon
2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001221-001252 ◽  
Author(s):  
Kei Murayama ◽  
Mitsuhiro Aizawa ◽  
Mitsutoshi Higashi

The bonding technique for High density Flip Chip(F.C.) packages requires a low temperature and a low stress process to have high reliability of the micro joining ,especially that for sensor MEMS packages requires hermetic sealing so as to ensure their performance. The Transient Liquid Phase (TLP) bonding, that is a kind of diffusion bonding is a technique that connects the low melting point material such as Indium to the higher melting point metal such as Gold by the isothermal solidification and high-melting-point intermetallic compounds are formed. Therefore, it is a unique joining technique that can achieve not only the low temperature bonding and also the high temperature reliability. The Gold-Indium TLP bonding technique can join parts at 180 degree C and after bonding the melting point of the junction is shifted to more than 495 degree C, therefore itfs possible to apply the low temperature bonding lower than the general use as a lead free material such as a SAC and raise the melting point more than AuSn solder which is used for the high temperature reliability usage. Therefore, the heat stress caused by bonding process can be expected to be lowered. We examined wafer bonding and F.C bonding plus annealing technique by using electroplated Indium and Gold as a joint material. We confirmed that the shear strength obtained at the F.C. bonding plus anneal technique was equal with that of the wafer bonding process. Moreover, it was confirmed to ensure sufficient hermetic sealing in silicon cavity packages that had been bonded at 180 degree C. And the difference of the thermal stress that affect to the device by the bonding process was confirmed. In this paper, we report on various possible application of the TLP bonding.


2012 ◽  
Vol 2012 (DPC) ◽  
pp. 002543-002566
Author(s):  
Daniel Harris ◽  
Robert Dean ◽  
Ashish Palkar ◽  
Mike Palmer ◽  
Charles Ellis ◽  
...  

Low–temperature bonding techniques are of great importance in fabricating MEMS devices, and especially for sealing microfluidic MEMS devices that require encapsulation of a liquid. Although fusion, thermocompression, anodic and eutectic bonding have been successfully used in fabricating MEMS devices, they require temperatures higher than the boiling point of commonly used fluids in MEMS devices such as water, alcohols and ammonia. Although adhesives and glues have been successfully used in this application, they may contaminate the fluid in the MEMS device or the fluid may prevent suitable bonding. Indium (In) possesses the unusual property of being cold weldable. At room temperature, two sufficiently clean In surfaces can be cold welded by bringing them into contact with sufficient force. The bonding technique developed here consists of coating and patterning one Si wafer with 500A Ti, 300A Ni and 1 μm In through electron beam evaporation. A second wafer is metallized and patterned with a 500A Ti and 1 μm Cu by electron beam evaporation and then electroplated with 10 μm of In. Before the In coated sections are brought into contact, the In surfaces are chemically cleaned to remove indium-oxide. Then the sections are brought into contact and held under sufficient pressure to cold weld the sections together. Using this technique, MEMS water-filled and mercury-filled microheatpipes were successfully fabricated and tested. Additionally, this microfabrication technique is useful for fabricating other types of MEMS devices that are limited to low-temperature microfabrication processes.


2012 ◽  
Vol 34 (8) ◽  
pp. 1327-1329 ◽  
Author(s):  
Wen-Jie Liu ◽  
Xiao-Long Hu ◽  
Jiang-Yong Zhang ◽  
Guo-En Weng ◽  
Xue-Qin Lv ◽  
...  

Author(s):  
Sethavut Duangchan ◽  
Yusuke Uchikawa ◽  
Yusuke Koishikawa ◽  
Baba Akiyoshi ◽  
Kentaro Nakagawa ◽  
...  

2007 ◽  
Vol 10 (7) ◽  
pp. 560-566 ◽  
Author(s):  
Toshinori OGASHIWA ◽  
Tadahiro SHIBUTANI ◽  
Masayuki MIYAIRI ◽  
Yoshitomo FUJISAWA ◽  
Kazunori TSURUMI ◽  
...  

Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.


Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.


Sign in / Sign up

Export Citation Format

Share Document