As a part of series of studies on X-Ray inspection technology to quantify solder defects in BGA balls,we have conducted inspection of 3 level POP package by using a new AXI that capable of 3D-CT imaging. The new results are compared with the results of earlier AXI measurements. It is found that 3D measurements offer better defect inspection quality,lower false call and escapes.

In a typical mechatronic manufacturing functional test setup,actual load simulations are usually done by connecting the DUT outputs to power or ground in order to establish either a high or low side driver. Each output is connected with different load and the test will either be sequential or concurrent. At lower power levels,these can usually be managed with general purpose switches. However,when it comes to higher power levels of currents more than 5 amps,such switching and loading might pose a greater challenge. Furthermore,critically in the manufacturing line,the tradeoff between cost and test time would have a great influence on the test strategy. This paper will present some key points to design a cost effective high power switching and load management solution. Firstly,we will discuss the selection process for the types of relays to be used in the switch methodology. Next,for automotive testing where high current measurements are typically done at the output channels,we will look into how this measurement is done; with or without loads and by instantaneous or continuous measurements. Then,we will discuss single load or multi load connections and explore different approaches. These connections provide simulation at different loading conditions. A typical example would be to emulate the steering wheel audio control button with different resistive loads. Subsequently,we will also discuss voltage protection and temperature cooling which are essential in such high power applications. Finally,we will give a bird eye’s view on the complete high level architecture of the combination of switch and load box,where usually the right solution is more than the sum of the parts. By providing the reader with guidance and tips on which design and methodology to adopt for the high power switch and load solutions,a cost effective while robust solution that promotes reusability of the test system in high mix test environment would be at your fingertips.

Reed relay is widely used in Automatic Test Equipment (ATE) for its high speed,low cost and wide availabilities. However,being mechanical relays,they have their share of limitations and this paper will try to address these challenges and explore alternatives such as solid state relays as replacement.

The SMT assembly world,especially within the commercial electronics realm,is dominated by no-clean solder paste technology. A solder paste flux residue that does not require removal is very attractive in a competitive world where every penny of assembly cost counts. One important aspect of the reliability of assembled devices is the nature of the no-clean solder paste flux residue. Most people in this field understand the importance of having a process that renders the solder paste flux residue as benign and inert as possible,thereby ensuring electrical reliability. But,of all the factors that play into the electrical reliability of the solder paste flux residue,is there any impact made by the age of the solder paste and how it was stored? This paper uses J-STD-004B SIR (Surface Insulation Resistance) testing to examine this question. Two commercially available SAC305,Type 4,no-clean solder pastes—one with a ROL0 and the other with a ROL1 J-STD-004B classification—were subjected to two different storage conditions (room temperature and refrigeration) and aged for varying lengths of time. After aging,the solder pastes were printed and reflowed using the same common reflow profile and then submitted to SIR testing to see what,if any,difference could be detected in their SIR performances. The reason for testing both a ROL0 and a ROL1 was to see if differences in chemistry could have an impact on how a solder paste ages relative to SIR performance.

Solder paste has long been viewed as “black magic”. This “black magic” can easily be dispelled through a solder paste evaluation. Unfortunately,solder paste evaluation can be a challenge for electronic assemblers. Interrupting the production schedule to perform an evaluation is usually the first hurdle. Choosing the solder paste properties to test is simple,but testing for these properties can be difficult. Special equipment or materials may be required depending upon the tests that are chosen. Once the testing is complete,how does one make the decision to choose a solder paste? Is the decision based on gut feel or hard data? This paper presents a process for evaluating solder pastes using a variety of methods. These methods are quick to run and are challenging,revealing the strengths and weaknesses of solder pastes. Methods detailed in this paper include: print volume,stencil life,response to pause,open time,tack force over time,wetting,solder balling,graping,voiding,accelerated aging,and others. Hard data is gathered and used in the evaluation process. Also presented in this paper are a set of methods that do not require expensive equipment or materials but still generate useful data. The goal is to help the electronics assembler choose the best solder paste for their process.

The transition from eutectic tin-lead to lead-free soldering in electronic assembly,mandatedby the RoHS legislation, has brought great pressure and challenge to solder material formulationdue to the high soldering temperature and high alloy surface tension. Moreover,the demand for halogen-free materials,which should be transparent toprocess yields,along withtheminiaturization trend in the electronic industry,is triggering arevolution in solder flux and paste formulations.The chemicalandmaterialinteractionsrelatedtosoldering andassemblyprocesses are many and varied. In general, the chemicals have to bestable during handling at mild temperaturesto warrant a process-friendlyshelf-life.Whileatpreheatandsoldering temperatures,thesolderfluxort h e pastehave to provide thermal transfer to the joint area and reactwiththemetallizationontheprintedcircuitboard(PCB) andcomponentleadstoremoveoxideandsurfacecontaminationinordertopreparethesurfaceforgood metallurgicalbonding,prevent re-oxidation with the atmosphere until the solder alloy re-solidifies,and promote wetting to form the joint.Residuescreatedbythefluxcontainmetalsalts,aswellasorganicandinorganic byproducts.A traditional formulation mainly relies on organic-based materials,rosins and carboxylic acidsto promote fluxing.Several attempts to understand the reactivity of organic acids and halogenated species have demonstrated the complexity of the chemical systems involved in fluxing mechanisms. Amine based formulations were mostly found in the old days,in the forms of ammonium orammonium halides. Here,we report a preliminary study aiming at giving some insight into the role of amines in electronic assembly applications. Our work shows that practical tests can be developed to characterize some fundamental properties of the activator packageswhich directly impact the final performance. The studyofinteractions between individual components within the systemis another key aspect of the design work.From that perspective,we intend to demonstrate that the formulator can develop robust formula based on scientific principles and rational studies rather than empirical knowledge and trial-and-error approaches.

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What’s the Future of Interposers for Semiconductor IC Packaging?

In today’s world it is important that a product has sufficient accreditation that it can be enter many different market places. While accreditation can be a costly process,it is prudent to know that your product is fit for purpose before going for accreditation. We propose a novel cost effective system for testing 100% of the LEDs (Light Emitting Diode) on a lighting product. This system will not only monitor the intensity and colour changes of a product while it is running but alert the engineer of early failures allowing the test to terminate,and faults to be examined. We propose this system as a rapid prototype tester. This system also allows unique LED changes to be monitored such as one LED to noticeably change while not changing the macro properties of the lighting unit. While a small change in individual LEDs or a small group of LEDs in a lighting product might not affect the accreditation process,it could have warrantee effects when the product is in the market
place. We will introduce the system,and show the results of five different LED based products being tested simultaneously over the course of three months. Each product consists of twenty LEDs,so we will monitor 100 LEDs simultaneously. The results will show unexpected behaviour of the LEDs,over the period of three months as a case study. We will show how such a system could be adapted for Standards such as IESNA LM-80 [1] and TM-21 [2]. Lastly we will show the advantage of pre-aging LED products to allow for improved lifetime estimation. While not a replacement for standards such as IESNA LM-80 [1] and TM-21 [2],the technique outlined above would allow smaller companies increased confidence in their product when getting a product range accredited. The system allow shorter prototype development times and hence a cost
saving to end-users.