Technical Library | 2008-11-13 00:06:32.0
The electronics industry is facing issues with hot spots, solder joint stresses and Coefficient of Thermal Expansion (CTE) mismatch between PCB and IC substrate. Flip chip type packages for example have very low CTE compared to traditional PCB material. Thus it is necessary to have low CTE printed circuit boards in order to keep solder joint intact with such low CTE packages. There are currently several materials available in the market to address thermal and CTE challenges but each material has its own advantages and limitations...
MMCC manufacturers light weight, high conductivity, low expansion graphite fiber reinforced aluminum and copper alloys. These alloys are fast machining, non magnetic, non toxic, and are easily plated. CTE's from 3-15 ppm/C and K's from 180-300 W/mK.
Industry Directory | Manufacturer
Thermally Managed ( up to 1000 W /m K thermal transfer rate ), CTE controlled, Very Rigid, Light Weight STABLCOR PCB / Substrate Technology
Technical Library | 2020-01-01 17:06:52.0
The majority of electronic failures occur due to thermally induced stresses and strains caused by excessive differences in coefficients of thermal expansion (CTE) across materials.CTE mismatches occur in both 1st and 2nd level interconnects in electronics assemblies. 1st level interconnects connect the die to a substrate. This substrate can be underfilled so there are both global and local CTE mismatches to consider. 2nd level interconnects connect the substrate, or package, to the printed circuit board (PCB). This would be considered a "board level" CTE mismatch. Several stress and strain mitigation techniques exist including the use of conformal coating.
Industry News | 2010-03-17 18:31:55.0
EAST HANOVER, NJ – Zymet has introduced a new silica-filled reworkable board-level underfill encapsulant, X2825, whose coefficient of thermal expansion, CTE, is 26 ppm/°C. The underfill enhances drop and shock test reliability and, compared to higher CTE underfills, provides superior thermal cycle performance.
Zymet's underfill encapsulants for flip chips are designed to enhance the thermal cycle performance. They incorporate silica filler, used to reduce the encapsulant’s CTE, that are highly engineered in both morphology and particle size distribution to
Technical Library | 1999-07-21 08:49:49.0
As the role of direct-chip-attachment increases in the electronics industry, the reliability and performance of COB packaging materials becomes an increasing concern. Although many factors influence component reliability, the biggest determinants of performance are often the glass transition temperature (Tg) and the coefficient of thermal expansion (CTE) of the encapsulant or underfill. This paper discusses exactly what these properties are, how they are measured, and why they are important to device-reliability.
Technical Library | 2008-02-04 12:13:38.0
Engineers are always striving to make a lighter, faster and stronger PCB. In order to achieve their designs, engineers must turn to alternative materials to enhance their designs. There are many materials that allow for thermal, coefficient of thermal expansion (CTE) and rigidity. Many times if a material enables an engineer to have CTE they will have to sacrifice thermal. Currently carbon composite laminates are being used in order to achieve an ideal PCB with thermal, CTE and rigidity with almost no weight premiums.
SMT256EP solderable adhesive is self-leveling and self-soldering adhesives, which has been designed for high temperature Pb-free application. By comparison with conductive adhesives (Ag), SMT256EP solderable adhesive has higher stable electrical and
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