Optimising process parameters for flip chip stencil printing using Taguchi's method

2002 ◽  
Author(s):  
D. Rajkumar ◽  
T. Nguty ◽  
N.N. Ekere
Keyword(s):  
Process Parameters ◽  
Flip Chip ◽  
Taguchi’S Method ◽  
Stencil Printing

A Study of the Aperture Filling Process in Solder Paste Stencil Printing

1999 ◽  
Author(s):  
Jianbiao Pan ◽  
Gregory L. Tonkay
Keyword(s):  
Flip Chip ◽  
Deposition Process ◽  
Area Ratio ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Surface Mount ◽  
Fine Pitch ◽  
Main Indicator ◽  
Advanced Packaging

Abstract Stencil printing has been the dominant method of solder deposition in surface mount assembly. With the development of advanced packaging technologies such as ball grid array (BGA) and flip chip on board (FCOB), stencil printing will continue to play an important role. However, the stencil printing process is not completely understood because 52–71 percent of fine and ultra-fine pitch surface mount assembly defects are printing process related (Clouthier, 1999). This paper proposes an analytical model of the solder paste deposition process during stencil printing. The model derives the relationship between the transfer ratio and the area ratio. The area ratio is recommended as a main indicator for determining the maximum stencil thickness. This model explains two experimental phenomena. One is that increasing stencil thickness does not necessarily lead to thicker deposits. The other is that perpendicular apertures print thicker than parallel apertures.

Process Characterization and the Effect of Process Defects on Flip Chip Reliability

1999 ◽  
Author(s):  
Brian J. Lewis ◽  
Hilary Sasso
Keyword(s):  
Process Parameters ◽  
Flip Chip ◽  
Failure Modes ◽  
Shock Testing ◽  
Fine Pitch ◽  
Process Characterization ◽  
Solder Bumps ◽  
Optimum Height ◽  
High Yields

Abstract Processing fine pitch flip chip devices continues to pose problems for packaging and manufacturing engineers. Optimizing process parameters such that defects are limited and long-term reliability of the assembly is increased can be a very tedious task. Parameters that effect the robustness of the process include the flux type and placement parameters. Ultimately, these process parameters can effect the long-term reliability of the flip chip assembly by either inhibiting or inducing process defects. Therefore, care is taken to develop a process that is robust enough to supply high yields and long term reliability, but still remains compatible with a standard surface mount technology process. This is where process optimization becomes most critical and difficult. What is the optimum height of the flux thin film used for a dip process? What force is required to insure that the solder bumps make contact with the pads? What are the limiting boundaries in which high yields and high reliabilities are achieved, while maintaining a streamlined, proven process? The following study evaluates a set of process parameters and their impact on process defects and reliability. The study evaluates process parameters including, flux type, flux application parameters, placement force and placement accuracy to determine their impact. Solder voiding, inadequate solder wetting, and crack propagation and delamination in the underfill layer are defects examined in the study. Assemblies will be subjected to liquid-to-liquid thermal shock testing (−55° C to 125°C) to determine failure modes due to the aforementioned defects. The results will show how changes in process parameters effect yield and reliability.

Electrolytic Solder Deposit for Next Generation Flip Chip Solder Bumping

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 000671-000707
Author(s):  
Stephen Kenny ◽  
Sven Lamprecht ◽  
Kai Matejat ◽  
Bernd Roelfs
Keyword(s):  
Flip Chip ◽  
Practical Experience ◽  
Electrolytic Deposition ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Advantages And Disadvantages ◽  
Novel Approach ◽  
Solder Bumps ◽  
Chip Attachment

Electrolytic Solder Deposit for Current methods for the formation of pre-solder bumps for flip chip attachment use stencil printing techniques with an appropriate solder paste. The continuing trend towards increasing miniaturisation and the associated decrease in size of solder resist opening, SRO is causing production difficulties with the stencil printing process. Practical experience of production yields has shown that stencil printing will not be able to meet future requirements for solder bump pitch production below 0.15 mm for these applications. This paper describes a novel approach to replace the stencil printing process by use of an electrolytic deposition of solder. In contrast to stencil printing, use of electrolytic deposition techniques allows production of solder bumps with a pitch below 0.15 mm and with a SRO below 80 μm. Methods for production of electrolytic solder bumps based on pure tin as well as alloys of tin/copper and also tin/silver are shown and in particular a method to control the alloy concentration of electroplated tin/copper bumps. Test results with both alloy systems and also pure tin bumping are presented together with comparison of the advantages and disadvantages. The general advantages of replacement of stencil printing by electrolytic deposition of solder bumps are shown and in particular the improvement of bump reliability and the potential to significantly decrease costs by yield improvement.

Fabrication of Carbon Nanotubes Reinforced Polyethylene Fibers by Melt Spinning: Process Optimization and Mechanical Strength Characterization

2007 ◽  
Vol 26-28 ◽  
pp. 289-292
Author(s):  
Abu Bakar Sulong ◽  
Joo Hyuk Park
Keyword(s):  
Carbon Nanotubes ◽  
Process Parameters ◽  
Melt Spinning ◽  
Polymer Fibers ◽  
Test Machine ◽  
Taguchi’S Method ◽  
Spinning Process ◽  
Strength Characterization ◽  
Surface Modified ◽  
Polyethylene Fibers

Optimization process for fabrication of Carbon nanotubes (CNTs) reinforced Polyethylene (PE) fibers by melt spinning has been studied. Three main melt spinning process parameters (spinning temperature, spinning distance, and spinning revolution) are evaluated by the Taguchi’s method to decrease the diameter of fibers. Decreasing diameter of fibers is greater influenced by spinning revolution and distance than spinning temperature. Moreover, fibers in diameter 22 μm (average) are successfully fabricated. Mechanical properties are measured by tensile test machine based on ASTM D3822 for single fibers which were fabricated at optimized melt spinning process parameters. Pure PE polymer fibers and chemically surface modified CNTs reinforced fibers also fabricated for comparison purpose. The interfacial bonding of CNTs with PE matrix is investigated through fracture surfaces image analysis by Scanning Electron Microscopy (SEM).

Experimental Investigation and Parameter Optimization of Micro Holes Machining on Ti-6Al-4V Alloy

2015 ◽  
Vol 813-814 ◽  
pp. 332-336
Author(s):  
R.A. Aravind ◽  
Shivakumar Ganesh ◽  
Syed Mohammed Yasir ◽  
G. Madhan Mohan ◽  
Vijayan Krishnaraj ◽  
...  
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Process Parameters ◽  
Electric Discharge ◽  
Optimum Process ◽  
Grinding Process ◽  
Taguchi’S Method ◽  
Electro Discharge Machining ◽  
Micro Holes ◽  
Variance Approach

This paper presents an experimental study on the diametrical overcut and taper obtained during the machining of micro holes by electro-discharge machining (EDM). Many trials were taken by machining a 2.0 mm electrolytic copper rod to 0.50 mm under various conditions to analyse the effect of process parameters by wire electric discharge grinding process (WEDG). The optimum process parameters were determined by Taguchi’s method. Then a set of electrodes were produced with the determined optimum process parameters and were used to machine micro holes on Ti-6Al-4V alloy. The diameters of the holes were measured and the effects of various parameters were analysed for the variation in taper and diametrical overcut. The experimental results were analysed using analysis of variance approach.

Sign in / Sign up

Export Citation Format

Share Document