How advanced low coefficient of thermal expansion (CTE) laminates and prepregs can improve the reliability of printed circuit boards (PCBs)

Circuit World ◽  
2003 ◽  
Vol 29 (1) ◽  
pp. 24-31 ◽  
Author(s):  
Michael Weinhold ◽  
George Yen
Keyword(s):  
Thermal Expansion ◽  
Printed Circuit Boards ◽  
Coefficient Of Thermal Expansion ◽  
Circuit Boards ◽  
Printed Circuit

Mounting Leadless Chip Carriers onto Printed Circuit Boards

1982 ◽  
Vol 1 (1) ◽  
pp. 38-43 ◽  
Author(s):  
D. Fishman ◽  
N. Cooper
Keyword(s):  
Thermal Expansion ◽  
Thermal Cycling ◽  
Printed Circuit Boards ◽  
Coefficient Of Thermal Expansion ◽  
Cycling Performance ◽  
Circuit Board ◽  
Circuit Boards ◽  
Acceptable Solution ◽  
Printed Circuit ◽  
Chip Carrier

It is reasoned that wide penetration of chip carriers into equipment for professional and commercial applications depends on developing methods for mounting the leadless types directly on to conventional polymer type printed circuit boards. The main problem to be overcome is fatigue failure of the solder joints due to the mismatch in thermal expansion, evidenced by poor thermal cycling performance. In this paper the thermal cycling performance is compared when four sizes of ceramic leadless chip carrier are mounted on a selection of printed circuit board materials ranging from the conventional to those specially formulated, either on the basis of matching the coefficient of thermal expansion of the chip carrier material, or to provide a layer of compliant elastomer material underneath the layer bearing the copper contact layer, so that strain due to thermal expansion mismatch is not transmitted to the solder layer. Over 400 thermal cycles (−55 to + 125°C) were recorded using proprietary versions of elastomer coated substrates. For appropriate applications the basis is thus laid for an economic and technically acceptable solution. The practical implications of two methods of soldering—wave (jet) and vapour phase—are also discussed.

Advanced Build-up Materials for High Speed Transmission Application

2018 ◽  
Vol 2018 (1) ◽  
pp. 000305-000309 ◽  
Author(s):  
Shiro Tatsumi ◽  
Shohei Fujishima ◽  
Hiroyuki Sakauchi
Keyword(s):  
High Speed ◽  
Printed Circuit Boards ◽  
Transmission Loss ◽  
Coefficient Of Thermal Expansion ◽  
Strip Line ◽  
Circuit Boards ◽  
Additive Process ◽  
Printed Circuit ◽  
Low Dielectric ◽  
Transmission Speed

Abstract Build-up process is a highly effective method for miniaturization and high density integration of printed circuit boards. Along with increasing demands for high transmission speed of electronic devices with high functionality, packaging substrates installed with semiconductors in such devices are strongly required to reduce the transmission loss. Our insulation materials are used in a semi-additive process (SAP) with low dielectric loss tangent, smooth resin surface after desmear, and good insulation reliability. Actually, the transmission loss of strip line substrates and Cu surface roughness impact on transmission loss were measured using our materials. Furthermore, low dielectric molding film with low coefficient of thermal expansion (CTE) and low Young's modulus are introduced.

Advanced Build-up Materials and Processes for Packages with Fine Line and Space

2014 ◽  
Vol 2014 (1) ◽  
pp. 000444-000447 ◽  
Author(s):  
Yoshio Nishimura ◽  
Hirohisa Narahashi ◽  
Shigeo Nakamura ◽  
Tadahiko Yokota
Keyword(s):  
Printed Circuit Boards ◽  
Coefficient Of Thermal Expansion ◽  
High Reliability ◽  
Electronic Devices ◽  
Circuit Boards ◽  
Additive Process ◽  
Fine Line ◽  
Printed Circuit ◽  
Low Dielectric ◽  
Line Space

Printed circuit boards manufactured by a semi-additive process are widely used for packaging substrates. Along with increasing demands of downsizing electronic devices with high functionality, packaging substrates installed with semiconductors in such devices are strongly required to be miniaturized with high density of circuit wirings. We report our insulation build-up materials and processes for advanced packages with fine line/space and high reliability. The insulation materials we developed show low coefficient of thermal expansion (CTE), low dielectric loss tangent and good thinner insulation reliability. They can produce fine line and space (FLS) under 10μm pitch by a semi-additive process.

COPPER/INVAR/COPPER

Alloy Digest ◽  
2004 ◽  
Vol 53 (1) ◽  
Keyword(s):  
Composite Material ◽  
Thermal Expansion ◽  
Printed Circuit Boards ◽  
Heat Treating ◽  
Heat Sinks ◽  
Circuit Boards ◽  
Annealed Condition ◽  
Roll Bonding ◽  
Printed Circuit ◽  
Metallic Composite Material

Abstract Copper/Invar/Copper is a wrought metallic composite material used in printed circuit boards, power planes, metal cores, hybrid enclosures, heat sinks, and other applications where coefficients of thermal expansion (CTE) match or where constraint of thermal expansion is required or beneficial. The laminated Cu/Invar/Cu composite material is metallurgically bonded by roll bonding and normally used in the fully annealed condition. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: FE-125. Producer or source: Engineered Materials Solutions Inc.

scholarly journals Thioetherimide-Modified Cyanate Ester Resin with Better Molding Performance for Glass Fiber Reinforced Composites

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1458 ◽  
Author(s):  
Pengchang Ma ◽  
Chuntao Dai ◽  
Shaohua Jiang
Keyword(s):  
Thermal Expansion ◽  
Glass Fiber ◽  
Printed Circuit Boards ◽  
Cyanate Ester ◽  
Reinforced Composites ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Glass Fiber Reinforced ◽  
Dimension Stability ◽  
Processing Properties

Cyanate ester (CE) resins with higher heat resistance, lower coefficients of thermal expansion (CTEs), and lower water absorption ratios are highly desired in printed circuit boards (PCBs). In this work, a CE was modified by copolymerization with a long-chain thioether bismaleimide (SBMI) to form a thioetherimide-modified CE (SBT). The results indicated that SBT had a wider processing window and better processing properties than a common bismaleimide-modified CE resin (MBMI). After molding with a glass fiber cloth, the composites (GSBT) exhibited moisture adsorption in the range of 1.4%–2.0%, high tensile strength in the range of 311–439 MPa, good mechanical retention of 70%–85% even at 200 °C, and good dimension stability, with coefficients of thermal expansion in the range of 17.3–18.6 (×10−6 m/°C). Such GSBT composites with superior properties would be good candidates for PCB applications.

High-Performance Thermoplastics for Rigid-Flex Printed Circuit Boards

1995 ◽  
Vol 390 ◽  
Author(s):  
Wendy W. Lin ◽  
Ender Savrun
Keyword(s):  
High Performance ◽  
Printed Circuit Boards ◽  
Adhesive Bonding ◽  
Coefficient Of Thermal Expansion ◽  
Performance Criteria ◽  
Screening Tests ◽  
Circuit Boards ◽  
Adhesive Failure ◽  
Fusion Bonding ◽  
Printed Circuit

ABSTRACTAdhesive failure of rigid-flex printed circuit boards (RF-PCBs) during use has degraded the performance of military avionics systems. Adhesive failure is often caused by differences in the coefficient of thermal expansion (CTE) between the materials used in RF-PCBs and by moisture absorption by the adhesives and polyimide (PI) films. High-performance thermoplastics were investigated to replace the epoxies, PIs, and adhesives currently used in RF-PCBs. Because thermoplastic materials are remeltable, adhesive bonding may be replaced by fusion bonding to join RF-PCBs. Fusion bonding would eliminate problems with material compatibility and differences in the CTE encountered with adhesive bonding. Industries that would benefit from this research are manufacturers of aerospace instrumentation, medical equipment, automotive systems, computers, telecommunications equipment, industrial instrumentation and controls, and consumer products, such as stereo systems and calculators.An extensive survey of high-performance-engineering thermoplastic materials was performed, and samples of the more promising materials (both films and chopped fiber reinforced) were obtained for preliminary screening tests. The tests performed were chemical resistance, water absorption, tensile strength, flexibility, and solder resistance of bare dielectric. From these tests, a glass-filled liquid crystal polymer film made by Hoescht Celanese Performance Films best met the performance criteria compared with the thermoplastics tested.

scholarly journals Materials Selection and Processing Techniques for Small Spacecraft Solar Cell Arrays

2011 ◽  
Vol 2011 (1) ◽  
pp. 000789-000799
Author(s):  
N. Meetra Torabi ◽  
Janet K. Lumpp ◽  
James E. Lumpp
Keyword(s):  
Thermal Expansion ◽  
Solar Cells ◽  
Solar Cell ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Cell Arrays ◽  
Carbon Core

Body mounted germanium substrate solar cell arrays form the faces of many small satellite designs to provide the primary power source on orbit. High efficiency solar cells are made affordable for University scale satellite programs as triangular devices trimmed from wafer scale solar cells. The smaller cells allow the array designs to pack tightly around antenna mounts and payload instruments, giving the board design more flexibility. We are investigating the reliability of solar cells attached to FR-4 and carbon core laminate printed circuit boards. FR-4 circuit boards have significantly higher thermal expansion coefficients and lower thermal conductivities than germanium. This thermal expansion coefficient mismatch between the FR-4 board and the components used cause major concern for the power system when considering a failure of the solar cells, such as a series of cracked cells or faulty solder joints. These failures are most likely to happen with a longer orbital lifetime and longer exposure to the harsh environment the satellite will experience while in orbit. Carbon core laminates provide an advanced alternative because the core thickness can be selected to more closely match the device substrate, or at least provide a wider thermal expansion coefficient range to match the components on the board. We are also comparing various methods of attaching the solar cells to the printed circuit boards, using solder paste alone and in parallel with a silicone adhesive, considering the application of these adhesives by comparing the solder joints under x-ray when applied by screen printing versus stencil printing, and looking closely at the cleaning processes for array assembly. Storage, vacuum exposure, thermal cycling, functional and vibration testing will be used to compare the survivability and performance of the solar arrays.

Development of High Heat Dissipation and Low Thermal Expansion Printed Circuit Boards

2020 ◽  
Vol 2020 (0) ◽  
pp. 0042
Author(s):  
Yohei Ito ◽  
Kenjiro Takanishi ◽  
Tatsuya Sakamoto ◽  
Keisuke Fujiwara ◽  
Hitoshi Arai
Keyword(s):  
Thermal Expansion ◽  
Printed Circuit Boards ◽  
Heat Dissipation ◽  
High Heat ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Low Thermal Expansion
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