Development of Accelerated Method for Thermal Cycling in Electronic Packaging Application

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Michael Mayer ◽  
Michael McCracken ◽  
John Persic
Keyword(s):  
Contact Resistance ◽  
Room Temperature ◽  
Cmos Technology ◽  
Standard Test ◽  
Maximum Temperature ◽  
Ball Bond ◽  
Voltage Application ◽  
Constant Operation ◽  
Released Energy ◽  
Ball Bonds

The method is based on a microheater integrated next to a wire bonding pad (test pad) on a test chip. It is fabricated in CMOS technology without additional micromachining. The microheater consists of two polysilicon resistor elements, placed at opposite sides of the pad, operated in parallel using a constant voltage, each element extending over 30 × 70 μm with a resistance of ≈140 Ω at room temperature, and is operated based on Joule heating. The polysilicon is located at least 20 μm but not more than 50 μm from the pad aluminum. To characterize the microheater, Al serpentine resistors are placed on and between the heaters next to the pad, serving as resistive temperature detectors, having resistances of about 9.4 Ω at room temperature. With a constant operation voltage of 15 V, ≈140 mA of current and ≈2.1 W of heating power are generated, resulting in a heat flux of ≈500 MW/m2. The thermal resistance of the heater is 200 K/W (i.e., loss coefficient of 5 mW/K). The maximum temperature measured on one of the microheater resistors was above 396 °C and was reached using 18 V within less than 5 s of voltage application starting at room temperature. When heating from 101 °C to 138 °C, even faster heating is possible, allowing the performance of highly accelerated thermocycles. These cycles are applied to a ball bond on the test pad. Compared to the 20 min cycles used by a standard test, the new microheater device performed cycles lasting 10 ms (5 ms on, 5 ms off) which is 5 orders of magnitude faster. The released energy is typically 10 mJ per cycle. A 50 μm diameter ball was made using 25 μm diameter Au wire and bonded to the test pad. The effect of the microheater-cycling on the contact resistance values of ball bonds is described. Starting with typical contact resistance values around 2.5 mΩ, the increase observed is between 4% and 7% after 5 × 106 10 ms cycles (≈14 h).

Simultaneous Electrical and Thermal Modeling of a Contact-Type RF MEMS Switch

2003 ◽  
Author(s):  
Brian Jensen ◽  
Zhongde Wang ◽  
Kazuhiro Saitou ◽  
John L. Volakis ◽  
Katsuo Kurabayashi
Keyword(s):  
Contact Resistance ◽  
Direct Contact ◽  
Rf Mems ◽  
Bulk Material ◽  
Thermal Contact ◽  
Electrical Contact ◽  
Maximum Temperature ◽  
Electrical Contact Resistance ◽  
Rf Mems Switch ◽  
Mems Switch

Improving the power handling capability of direct contact RF MEMS switches requires a knowledge of conditions at the contact. This paper models the temperature rise in a direct contact RF MEMS switch, including the effects of electrical and thermal contact resistance. The maximum temperature in the beam is found to depend strongly on the power dissipation at the contact, with almost no contribution from dissipation due to currents in the rest of the switch. Moreover, the maximum temperature is found to exceed the limit for metal softening for a significant range of values of thermal and electrical contact resistance. Since local contact asperity temperature can be hundreds of degrees higher than the bulk material temperature modeled here, these results underscore the importance of understanding and controlling thermal and electrical contact resistance in the switch.

Ni-Al-Ti Ohmic Contacts with Preserved Form Factor and Few 10- 4 Ωcm2 Specific Resistance on 0.1-1 Ωcm p-Type 4H-SiC

2018 ◽  
Vol 924 ◽  
pp. 385-388 ◽  
Author(s):  
Roberta Nipoti ◽  
Maurizio Puzzanghera ◽  
Maria Concetta Canino ◽  
Giovanna Sozzi ◽  
Paolo Fedeli
Keyword(s):  
Form Factor ◽  
Contact Resistance ◽  
Contact Area ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Specific Resistance ◽  
Thickness Ratio ◽  
Specific Contact Resistance ◽  
Specific Contact ◽  
P Type

This study shows that a thin Ni film on Al/Ti/4H-SiC metal pads allows to preserve the pad form factor during a 1000 °C/2 min treatment, provided that the Al and Ti film thicknesses are sufficiently thin. Moreover, by reducing the Al to Ti thickness ratio, droplet formation in the contact area is avoided and a mirror-like appearance is obtained. This optimal contact morphology corresponds to a specific contact resistance of few 10-4Ωcm2at room temperature on p-type 4H-SiC with resistivity in the range 0.1 – 1 Ωcm.

High Temperature Storage Reliability of Bond Resistance of Palladium-Coated Copper Ball Bonds

2017 ◽  
Vol 2017 (1) ◽  
pp. 000432-000437 ◽  
Author(s):  
Michael David Hook ◽  
Michael Mayer ◽  
Stevan Hunter
Keyword(s):  
High Temperature ◽  
Ball Bond ◽  
Wire Bonds ◽  
High Temperature Storage ◽  
Ball Bonding ◽  
Ball Bonds ◽  
Bond Pads ◽  
Wire Resistance ◽  
Temperature Storage

Abstract Reliability of wire bonds made with palladium-coated copper (PCC) wire of 25 μm diameter is studied by measuring the wire bond resistance increase over time in high temperature storage at 225 °C. Ball bonds are made on two bond pad thicknesses and tested with and without mold compound encapsulation. Bond pads are aluminum copper (Al-0.5%Cu), 800 nm and 3000 nm thick. The wirebonding pattern is arranged to facilitate 4-wire resistance measurements of 12 bond pairs in each 28-pin ceramic test package. The ball bonding recipe is optimized to minimize splash on 3000 nm Al-0.5%Cu with shear strength at least 120 MPa. Ball bond diameter is 61 μm and height is 14 μm. Measurements include bond shear test data and in-situ resistance before and during high temperature storage. Bonds on 3000 nm pads are found to be significantly more reliable than bonds on 800 nm pads within 140 h of aging.

Experimental and Simulation Studies of Thermal Distribution on Modified Connector of Li-Ion Battery for Electric Vehicles Application

2016 ◽  
Vol 6 (5) ◽  
pp. 2064
Author(s):  
Agus Risdiyanto ◽  
Umar Khayam ◽  
Noviadi A. Rachman ◽  
Maulana Arifin
Keyword(s):  
Contact Resistance ◽  
Contact Area ◽  
Fire Hazard ◽  
Lithium Ion ◽  
Maximum Temperature ◽  
Silver Coating ◽  
Li Ion Battery ◽  
Steady State Condition ◽  
Li Ion ◽  
Dc Current

<p>One of the several failure cases in electric vehicle could be occured at the Lithium-ion (Li-ion) battery connectors when loaded by high current. This failure caused by bad contact of connectors so that the contact resistance increase and lead to high power losses, overheating, and it can even cause a fire hazard. This paper presents a thermal distributions of  Li-ion battery connectors on different coating material in relation to the value of contact resistance. There were two test samples of modeled: copper connection without coating and copper connection with silver coating. Each sample was loaded by the DC current of 350A, and temperature at the connection was measured until steady state condition reached and simulated by Solidwork software. The results show that the temperature at the inside contact area was higher than the outside contact area of connection that appears caused by higher of the contact resistance. Both measurement and simulation results have same tendency that copper connection with silver coating having lower contact resistance, lower maximum temperature, and lower losses about 32 % than copper connection without  coating. Silver coating can be considered as other alternative to prevent overheating, high losses, and failure in Li-ion battery connector.</p>

Effect of Maximum Temperature and Heating-Cooling Repeated Cycles on Thermal Contact Resistance of a Composite Tube

2009 ◽  
Vol 15 ◽  
pp. 41-46 ◽  
Author(s):  
I. Carvajal-Mariscal ◽  
F. Sánchez-Silva ◽  
G. Polupan ◽  
J.A. Basualdo-Rojo
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Optimal Operation ◽  
Thermal Design ◽  
Maximum Temperature ◽  
Operational Parameter ◽  
Repeated Heating ◽  
Operational Temperature ◽  
Copper Aluminum

Experimental research results of the operational parameter effect on Thermal Contact Resistance (TCR) in a copper-aluminum L-type finned tube are presented. The investigated operational parameters were the maximum operational temperature and the number of repeated heating-cooling cycles. The TCR was experimentally determined by measuring the total heat supply, core tube wall and inner fin surface temperatures for steady-state and natural-convection conditions. In addition, the specimen was tested through up to 200 heating-cooling cycles. The experimental results showed a TCR increase of 81% at the same time as the average temperature difference between the hot inner flow and cooling air increased from 30°C to 130°C; over the maximum operational temperature (120°C), the TCR increased faster than before; and, after the heating-cooling cycle testing the TCR presented an increase of 31% in respect with the initial value. Such findings may be useful as a reference for preliminary thermal design and as recommendations for optimal operation of heat exchangers based on copper-aluminum L-type finned tubes.

Bondability and Strength Evaluation of Gold Ball Bond Using Nanoindentation Approach

2016 ◽  
Vol 700 ◽  
pp. 132-141
Author(s):  
Muhammad Nubli Zulkifli ◽  
Azman Jalar ◽  
Shahrum Abdullah ◽  
Norinsan Kamil Othman
Keyword(s):  
Wire Bonding ◽  
Strength Distribution ◽  
Nanoindentation Test ◽  
Ball Bond ◽  
New Approach ◽  
Bonding Parameter ◽  
Responsible Mechanism ◽  
Reduced Modulus ◽  
Gold Ball ◽  
Ball Bonds

The evaluation of the strength and bondability of gold, Au ball bond requires a new approach to provide a more detail data. Nanoindentation test was used as a new approach to evaluate the strength distribution and bondability of Au ball. Au ball bonds that experienced different value of wire bonding parameter namely bonding force, bonding time, bonding power, and stage temperature were used as samples for the present analysis. The distribution of strength based on hardness and reduced modulus values located at the bonding area of Au ball bonds were found to be related with the values of the wire bonding parameter. Nanoindentation test was found to be a suitable approach to analyze and evaluate the bondability of Au ball bond in a localized and detailed manner. In addition, the responsible mechanism for the thermosonic Au wire bonding can be identified and analyzed by using the results obtained from the nanoindentation test.

scholarly journals Formation of MgO:LiNbO3 Domain-Inverted Gratings by Voltage Application under UV Light Irradiation at Room Temperature

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Masatoshi Fujimura ◽  
Toshiaki Suhara
Keyword(s):  
Nonlinear Optic ◽  
Room Temperature ◽  
Uv Light ◽  
Lateral Expansion ◽  
Cladding Layer ◽  
Uv Light Irradiation ◽  
Voltage Application ◽  
Formation Method ◽  
Domain Inversion ◽  
Photolithography Process

MgO:LiNbO3 is an attractive nonlinear-optic crystal for quasiphasematched (QPM) nonlinear-optic devices. This paper reports a new formation method of domain-inverted gratings for QPM in MgO:LiNbO3. Domain inversion of MgO:LiNbO3 by voltage application under UV light was characterized, and reduction of the voltage required for inversion was demonstrated. Results of voltage application under periodic UV light suggested that suppression of excess lateral expansion of the domain inverted regions on −Z surface was crucial for domain-inverted grating formation. Voltage application to a crystal with a photoconductive cladding layer under periodic UV light was proposed. The cladding layer suppressed the expansion, and the domain-inverted gratings with period of 18 μm and area of 25×5 mm2 were obtained. The formation method does not require the photolithography process and allows the formation by voltage application at room temperature, and therefore, is quite simple and productive.

TiW/TiWN/Pt Ohmic Contacts to n-Type 3C-SiC

2006 ◽  
Vol 911 ◽  
Author(s):  
Kirk Hofeling ◽  
Loren Rieth ◽  
Florian Solzbacher
Keyword(s):  
Contact Resistance ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Test Duration ◽  
Capping Layer ◽  
Interface Reactions ◽  
Transmission Line Method ◽  
Specific Contact

AbstractTiW(40 nm)/TiWN(80 nm)/Pt(500nm) was investigated as a new high-temperature compatible contact stack to 3C-SiC for harsh environment applications. Performance of TiW/TiWN/Pt contacts deposited on unintentionally doped (8.85×1018 cm-3) 3C-SiC grown by LPCVD to a thickness of ~1μm on (100) Si are reported. The linear transmission line method was used to determine specific contact resistance (ρc) at room temperature and for long-term tests at 300 °C. As deposited contacts were Ohmic with a ρc range of 1×10-4 to 1×10-3 &#61527;cm2. These contacts were annealed for five minutes in forming gas (8% H2 92% Ar), at temperatures from 450 to 950 °C and all retained Ohmic character. Annealing samples at 450, 550 and 950 °C decreased ρc while anneling between 650 and 850 °C generally increased ρc.Auger Electron Spectroscopy (AES) analysis was performed on a sample annealed at 750 °C. The as-received surface was composed of Si and O; after a brief sputter etch a characteristic Pt peak became visible and the O peak decreased substantially. Depth profiles detected Si throughout the Pt capping layer but not in the TiW layers. We suspect that Si diffuses from the SiC substrate into the Pt capping layer and surface Si also reacts with O2 to from an oxide. These reactions, in combination with incomplete SiC/TiW interface reactions, are suspected to cause the increase of ρc for samples annealed between 650 and 850 °C. Annealing at 950 °C gave the lowest contact resistance of 2.3×10-5. Long-term testing at 300 °C for 190 hours, in atmosphere, was performed on contacts annealed at 450 °C. When heated, the contacts initial ρc of 2.1×10-4 &#61527;cm2 increased to ~4×10-3 &#61527;cm2 which remained stable for the test duration. After long-term testing the sample ρc measured at room temperature decreased to 9.8×10-5 &#61527;cm2.

Electrical Characterization of Nitrogen Implanted 3C-SiC by SSRM and C­TLM Measurements

2011 ◽  
Vol 679-680 ◽  
pp. 193-196 ◽  
Author(s):  
Xi Song ◽  
Anne Elisabeth Bazin ◽  
Jean François Michaud ◽  
Frédéric Cayrel ◽  
Marcin Zielinski ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Room Temperature ◽  
Electrical Characterization ◽  
Specific Contact Resistance ◽  
Nitrogen Implantation ◽  
Transfer Length ◽  
Characterization Methods ◽  
Activation Rate ◽  
Specific Contact ◽  
Titanium Nickel

Two electrical characterization methods were used to study 3C-SiC epilayers doped by nitrogen implantation: circular Transfer Length Method (c­TLM) which allows extracting the specific contact resistance and Scanning Spreading Resistance Microscopy (SSRM) used to measure activated doping concentration. 3C-SiC samples were implanted at room temperature with different energies (ranging from 30 to 150keV) and doses (from 1 to 5.4x1015cm-2) in order to obtain a 300nm thick box-like profile at 5x1020cm-3. To activate the dopant, the samples were then annealed from 1150°C to 1350°C for 1h to 4h. Titanium-nickel c-TLM contacts annealed at 1000°C under argon showed the best results in terms of specific contact resistance (8x10-6.cm2) after a 1350°C–1h annealing. For this annealing condition, the activation rate was assessed by SSRM around 13%. This value confirms the difficulty to activate the dopants introduced into the 3C-SiC as the temperature is limited by the silicon substrate. However, this work demonstrates that low resistance values can be achieved on 3C-SiC, using nitrogen implantation at room temperature.

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