Shock and Vibration of Solder Bumped Flip Chip on Organic Coated Copper Boards

1996 ◽  
Vol 118 (2) ◽  
pp. 101-104 ◽  
Author(s):  
John Lau ◽  
Eric Schneider ◽  
Tom Baker
Keyword(s):  
Mathematical Analysis ◽  
Flip Chip ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Plane Shock ◽  
Printed Circuit ◽  
Flip Chips ◽  
Solder Bumps ◽  
Out Of Plane ◽  
Vibration Tests

The reliability of solder bumped flip chips on organic coated copper (OCC) printed circuit board (PCB) has been studied by shock and vibration tests and a mathematical analysis. Two different chip sizes (7 mm and 14 mm on a side) have been studied, and the larger chips have many internal solder bumps. For the in-plane and out-of-plane and out-of-plane shock tests, the chips were assembled with and without underfill encapsulants. However, for the out-of-plane vibration tests all the chips were underfilled with epoxy.

Modelling the Performance of Lead-Free Solder Interconnects for Copper Bumped Flip-Chip Devices

2003 ◽  
Author(s):  
Hua Lu ◽  
Chris Bailey
Keyword(s):  
Flip Chip ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Conductive Adhesives ◽  
Solder Interconnects ◽  
Flip Chips ◽  
Solder Bumps ◽  
Solder Volume ◽  
Joint Properties ◽  
Free Solder

Traditionally, before flip chips can be assembled the dies have to be attached with solder bumps. This process involves the deposition of metal layers on the Al pads on the dies and this is called the under bump metallurgy (UBM). In an alternative process, however, Copper (Cu) columns can be used to replace solder bumps and the UBM process may be omitted altogether. After the bumping process, the bumped dies can be assembled on to the printed circuit board (PCB) by using either solder or conductive adhesives. In this work, the reliability issues of flip chips with Cu column bumped dies have been studied. The flip chip lifetime associated with the solder fatigue failure has been modeled for a range of geometric parameters. The relative importance of these parameters is given and solder volume has been identified as the most important design parameter for long-term reliability. Another important problem that has been studied in this work is the dissolution of protection metals on the pad and Cu column in the reflow process. For small solder joints the amount of Cu which dissolves into the molten solder after the protection layers have worn out may significantly affect solder joint properties.

Experimental Investigation by Speckle Interferometry of Solder Joint Failure Under Thermomechanical Load Aggravated by Boundary Conditions at Board Level

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
D. N. Borza ◽  
I. T. Nistea
Keyword(s):  
Solder Joint ◽  
Fundamental Frequency ◽  
Printed Circuit Board ◽  
Speckle Interferometry ◽  
Circuit Board ◽  
Joint Failure ◽  
Printed Circuit ◽  
Out Of Plane ◽  
Fringe Patterns ◽  
Board Level

Reliability of electronic assemblies at board level and solder joint integrity depend upon the stress applied to the assembly. The stress is often of thermomechanical or of vibrational nature. In both cases, the behavior of the assembly is strongly influenced by the mechanical boundary conditions created by the printed circuit board (PCB) to casing fasteners. In many previously published papers, the conditions imposed to the fasteners are mostly aiming at an increase of the fundamental frequency and a decrease of static or dynamic displacement values characterizing the deformation. These conditions aim at reducing the fatigue in different parts of these assemblies. In the photomechanics laboratory of INSA Rouen, the origins of solder joint failure have been investigated by means of full-field measurements of the flexure deformation induced by vibrations or by forced thermal convection. The measurements were done both at a global level for the whole printed circuit board assembly (PCBA) and at a local level at the solder joints where failure was reported. The experimental technique used was phase-stepped laser speckle interferometry. This technique has a submicrometer sensitivity with respect to out-of-plane deformations induced by bending and its use is completely nonintrusive. Some of the results were comforted by comparison with a numerical finite elements model. The experimental results are presented either as time-average holographic fringe patterns, as in the case of vibrations, or as wrapped phase patterns, as in the case of deformation under thermomechanical stress. Both types of fringe patterns may be processed so as to obtain the explicit out-of-plane static deformation (or vibration amplitude) maps. Experimental results show that the direct cause of solder joint failure may be a high local PCB curvature produced by a supplementary fastening screw intended to reduce displacements and increase fundamental frequency. The curvature is directly responsible for tensile stress appearing in the leads of a large quad flat pack (QFP) component and for shear in the corresponding solder joints. The general principle of increasing the fundamental frequency and decreasing the static or dynamic displacement values has to be checked against the consequences on the PCB curvature near large electronic devices having high stiffness.

scholarly journals A Diffusor/Nozzle Pump Based on a Magnetically Actuated Flexible PCB Diaphragm

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1077
Author(s):  
Marcus A. Hintermüller ◽  
Bernhard Jakoby
Keyword(s):  
Printed Circuit Board ◽  
Microfluidic Channel ◽  
Circuit Board ◽  
Fabrication Method ◽  
Flexible Membrane ◽  
Printed Circuit ◽  
Magnetically Actuated ◽  
Lorentz Forces ◽  
Out Of Plane ◽  
Flexible Printed Circuit

We present a valveless microfluidic pump utilizing an oscillating membrane made from a flexible printed circuit board. The microfluidic channel is fabricated by a 3D printing process and features diffuser/nozzle structures to obtain a directed flow; the flexible membrane is bonded to the channel. The membrane is actuated via Lorentz forces to accomplish out-of-plane motions and push the fluid through the channel. A permanent magnet provides the static magnetic field required for the actuation. The simple fabrication method can potentially be used for inexpensive mass fabrication for disposable devices.

scholarly journals Development of 6 U CubeSat’s Deployable Solar Panel with Burn Wire Triggering Holding and Release Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Tae-Yong Park ◽  
Bong-Geon Chae ◽  
Hyun-Ung Oh
Keyword(s):  
Random Vibration ◽  
Printed Circuit Board ◽  
Solar Panel ◽  
Circuit Board ◽  
Structural Safety ◽  
Release Mechanism ◽  
Printed Circuit ◽  
Test Conditions ◽  
Wire Cutting ◽  
Vibration Tests

In the present work, a deployable solar panel based on a burn wire triggering holding and release mechanism was developed for use of 6 U CubeSat. The holding and release mechanism was designed based on a nichrome burn wire cutting method widely used for CubeSat applications. However, it provides a high loading capability, reliable wire cutting, multiplane constraints, and handling simplicity during the tightening process of wire. A demonstration model of a printed circuit board-based solar panel stiffened by a high-pressure fiberglass-laminated G10 material was fabricated and tested to validate the effectiveness of the design and functionality of the mechanism under various test conditions. The structural safety of the solar panel combined with the mechanism in a launch vibration environment was verified through sine and random vibration tests at qualification level.

Rapid Prototyping Tape Stencils for the Application of Solder Paste

2017 ◽  
Vol 2017 (1) ◽  
pp. 000652-000658
Author(s):  
Mimi X. Yang ◽  
Karen Dowling ◽  
Debbie Senesky ◽  
H.-S. Philip Wong
Keyword(s):  
Rapid Prototyping ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Solder Paste ◽  
Electrically Conductive ◽  
Printed Circuit ◽  
Solder Bumps ◽  
Small Device ◽  
Bond Pads ◽  
Silicon Device

Abstract This works describes a promising method for rapid prototyping tape stencils for the application of solder paste. This process is appropriate for research settings requiring developmental flexibility and the ability to deal with small device dies. This work compares the volume of solder paste deposited versus aperture volume for several common tape materials and several common printed circuit board (PCB) stencil materials. The solder deposits are then reflowed to identify which aperture and solder paste parameters can generate successful solder bumps. Electrically conductive solder bonds for small bond pads (100 μm and larger) are demonstrated between silicon device dies and glass dies using this process.

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