Fabrication of Cofired ALN Multilayer Substrates at Low Temperature Sintering

1993 ◽  
Vol 323 ◽  
Author(s):  
Koichi Terao ◽  
Ichiro Uchiyama ◽  
Akihiro Hamano
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Low Temperature ◽  
Oxygen Content ◽  
Substrate Material ◽  
Low Temperature Sintering ◽  
Dense Microstructure ◽  
High Adhesion ◽  
Porous Microstructure ◽  
Powder Properties

AbstractIn order to lower the firing temperature of W cofired AlN multilayer substrates, sinterabilities of AlN substrate material and W conductor were investigated at low sintering temperatures around 1650 •C.In case of AIN substrate material, the effect of AIN powder properties on sinterability and thermal conductivity was evaluated. The powders, with specific surface area between 2.3 and 8.2m2• g−1 and oxygen content between 0.7 and 3.2 wt%, were sintered with CaO and Y2O3 as sintering additives. The finer powder promoted the densification below 1600°C and each powder was fully densified at 1650°C. However thermal conductivity sintered at 1650°C decreased with decreasing particle size due to increasing oxygen content inside AlN grains. The thermal conductivity of optimized AlN substrate sintered at 1650°C had over 100W • m−1 K−1.W conductor is required dense microstructure for high adhesion strength to AlN substrate. Shrinkage mismatch between AlN and W during sintering caused porous microstructure for coarse W powders or detaching for fine W powders. The optimized W paste was developed for low temperature sintering.

Grinding of Agglomerate AlN Powder by Wet Milling

2006 ◽  
Vol 317-318 ◽  
pp. 45-48
Author(s):  
Jin Yu Qiu ◽  
Koji Watari ◽  
Yuji Hotta ◽  
Yoshiaki Kinemuchi ◽  
Kenshi Mitsuishi
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Ball Mill ◽  
Planetary Mill ◽  
Size Reduction ◽  
Low Temperature Sintering ◽  
Wet Milling ◽  
Fine Grinding ◽  
Better Than ◽  
Grinding Mill

Fine AlN powder doped with Y2O3 and CaO as sintering additives was ground by a ball mill, a planetary ball mill and a super-fine grinding mill in order to obtain fine homogenous powder for low-temperature sintering. The size reduction and the sinterability of ground powders at 1500oC for 6 h were investigated. The size and shape of the agglomeration showed no significant change after the ball mill and planetary mill processes, resulting in poor densification. On the contrary, AlN particles with size of 50~100 nm was pulverized and dispersed by a super-fine grinding mill with very small ZrO2 beads as a mill media. The microstructures of the specimen exhibited equiaxed and homogenous grains with size of 0.3~0.4 μm. Pores in the specimens were eliminated. The thermal conductivity was 70W/mK, which is better than that of Al2O3 ceramics (~20W/mK).

Low Temperature Sintering of Alumina by CuO-TiO2-Nb2O5 Additives

2006 ◽  
Vol 320 ◽  
pp. 181-184 ◽  
Author(s):  
Koichi Shigeno ◽  
Hidenori Katsumura ◽  
Hiroshi Kagata ◽  
Hiroshi Asano ◽  
Osamu Inoue
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Mixed Oxide ◽  
Low Temperature Sintering ◽  
Sintering Additives ◽  
Additive Content

We examined sintering additives for alumina. When using CuO-TiO2-Nb2O5 additive, dense sintered alumina was obtained by firing at 1000°C or below, even though additive content was at most 10 mass%. It is considered that the formation of mixed oxide consists of CuO, TiO2 and Nb2O5 has an important role for low temperature sintering of alumina. Thermal conductivity of the above sample was 15 W/mK, which was the highest value yet reported within LTCC (Low Temperature Co-fired Ceramics) materials.

Microstructure and Thermal Conductivity of AlN(Y2O3) Ceramics

2000 ◽  
Vol 6 (S2) ◽  
pp. 422-423
Author(s):  
Y. D. Yu ◽  
A. M. Hundere ◽  
R. Høier ◽  
M. -A. Einarsrud ◽  
R. E. Dunin-Borkowski
Keyword(s):  
Thermal Conductivity ◽  
Liquid Phase ◽  
Oxygen Content ◽  
Secondary Phase ◽  
Graphite Crucible ◽  
Substrate Material ◽  
Liquid Phase Sintering ◽  
Powder Bed ◽  
Gas Tight ◽  
Potential Substrate

Aluminum nitride (AIN) with high thermal conductivity has been considered as a potential substrate material for microelectronics. However, the thermal conductivity of polycrystalline AIN ceramics, prepared by liquid-phase sintering, is significantly lower than that of AIN single crystal. It has been shown that the thermal conductivity of AIN is inversely proportional to the oxygen content dissolved in the AIN lattice. Furthermore, the microstructure of AIN can also influence the thermal conductivity considerably. In the present study, we investigated the effect of grain boundaries and secondary phase distributions on thermal conductivity of two selected high density samples which contained similar oxygen content but showed different thermal conductivities.Experimental details and selected properties of Samples A and B are shown in Table 1. Sample A with 0.8 wt% Y2O3 additive was embedded in an AIN powder bed in a BN crucible covered by a BN lid (not gas tight) during sintering, while Sample B with 3.9 wt% Y2O3 was embedded in an AIN powder bed in an open graphite crucible.

scholarly journals Investigation of the Thermo-Physical and Mechanical Properties of Coir and Sugarcane Bagasse for Low Temperature Insulation

2021 ◽  
Vol 6 (4) ◽  
pp. 340-356
Author(s):  
Mustapha Ndagi ◽  
Ajiboye Tajudeen Kolawole ◽  
Fabiyi Mustapha Olawale ◽  
Abdulkareem Sulaiman
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Low Temperature ◽  
Sugarcane Bagasse ◽  
Control Sample ◽  
Gum Arabic ◽  
Absorption Capacity ◽  
Thermal Resistivity ◽  
Insulating Materials ◽  
Insulating Material

This research  reports on the suitability of Agricultural bi-products as low temperature thermal insulating materials to replace synthetic insulating materials like polyurethane used in food warmers and ice coolers. Coir and sugarcane bagasse chosen for this research was based on literature review and local availability of materials. Coir was obtained from Badagry, Lagos State and Sugarcane bagasse obtained from Batati, Niger State, the materials were washed, sun dried for three days and cut into smaller pieces before being blended into smaller particles using an electric blender. The blended materials (Coir and Bagasse) were sieved into two different sieve size of 0.5 mm and 1.0 mm respectively.  The particles sizes were then combined into blend ratios of 50/50, 60/40, and 70/30 using Gum Arabic as binder. Thermal conductivity test showed that 1.0 mm particle size coir mixed with sugarcane bagasse has the lowest thermal conductivity of 0.01467 W/mK whilst that of 0.5 mm particle size has thermal conductivity of 0.01472 W/mK this is lower compared to the measured thermal conductivity of the polyurethane control sample of 0.01832 W/mK. Sample F (1.0 mm particle size,70% coir and 30% bagasse) with a thermal diffusivity of 5.15  m²/s, water absorption capacity of 410 %, UTS of 0.219 MPa, Compressive strength of 0.583 MPa, Specific heat capacity of 1141.3 J/kgK and thermal resistivity of 68.16 W/m/K is most suitable replacement for polyurethane as low temperature thermal insulator. This is corroborated by the performance evaluation test with carried out between polyurethane lined food warmer and bio-composite lined food warmer. The two test samples have close ice melt rate values and the polyurethane slightly edge the Bio-composite insulating material by 1.2 % in efficiency. The edge in efficiency can be accepted as all materials used in the development of the bio-composite insulating material are completely bio-degradable and environmentally friendly.

Thermal Conductivity of Al2O3/Glass/CfComposite Substrates Prepared by Low Temperature Sintering

2015 ◽  
Vol 74 (4) ◽  
pp. 213-217 ◽  
Author(s):  
S. X. Wang ◽  
G. S. Liu ◽  
X. Q. Ouyang ◽  
Y. D. Wang ◽  
D. Zhang
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Low Temperature Sintering
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