ÿþ<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><!-- InstanceBegin template="/Templates/empfasis-article_newtmp.dwt" codeOutsideHTMLIsLocked="false" --> <head> <!-- InstanceBeginEditable name="Head" --><title>Empfasis - Tech Tips: Microscopy in Failure Analysis</title> <!-- InstanceEndEditable --> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <style type="text/css"> <!-- @import url(http://www.empf.org/empfasis/emphasis.css); .style1 { font-size: 16px; font-weight: bold; color: #1A2A57; } .style5 {font-size: 14px; font-weight: bold; } .style6 { color: #1A2A57; font-weight: bold; } .style7 {font-family: Arial, Helvetica, sans-serif} .style9 { font-size: 12px; font-weight: bold; color: #1A2A57; } .style14 {font-size: 10} .style17 {font-size: 12px} .style24 {color: #1A2A57; font-weight: bold; font-size: 14px; } --> </style> <script language="JavaScript" type="text/JavaScript"> <!-- function MM_preloadImages() { //v3.0 var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array(); var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++) if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}} } function MM_findObj(n, d) { //v4.01 var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) { d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);} if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n]; for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document); if(!x && d.getElementById) x=d.getElementById(n); return x; } function MM_nbGroup(event, grpName) { //v6.0 var i,img,nbArr,args=MM_nbGroup.arguments; if (event == "init" && args.length > 2) { if ((img = MM_findObj(args[2])) != null && !img.MM_init) { img.MM_init = true; img.MM_up = args[3]; img.MM_dn = img.src; if ((nbArr = document[grpName]) == null) nbArr = document[grpName] = new Array(); nbArr[nbArr.length] = img; for (i=4; i < args.length-1; i+=2) if ((img = MM_findObj(args[i])) != null) { if (!img.MM_up) img.MM_up = img.src; img.src = img.MM_dn = args[i+1]; nbArr[nbArr.length] = img; } } } else if (event == "over") { document.MM_nbOver = nbArr = new Array(); for (i=1; i < args.length-1; i+=3) if ((img = MM_findObj(args[i])) != null) { if (!img.MM_up) img.MM_up = img.src; img.src = (img.MM_dn && args[i+2]) ? args[i+2] : ((args[i+1])? args[i+1] : img.MM_up); nbArr[nbArr.length] = img; } } else if (event == "out" ) { for (i=0; i < document.MM_nbOver.length; i++) { img = document.MM_nbOver[i]; img.src = (img.MM_dn) ? img.MM_dn : img.MM_up; } } else if (event == "down") { nbArr = document[grpName]; if (nbArr) for (i=0; i < nbArr.length; i++) { img=nbArr[i]; img.src = img.MM_up; img.MM_dn = 0; } document[grpName] = nbArr = new Array(); for (i=2; i < args.length-1; i+=2) if ((img = MM_findObj(args[i])) != null) { if (!img.MM_up) img.MM_up = img.src; img.src = img.MM_dn = (args[i+1])? args[i+1] : img.MM_up; nbArr[nbArr.length] = img; } } } //--> </script> </head> <body onLoad="MM_preloadImages('http://www.empf.org/empfasis/nav/images/empfasis_nav_01-over.gif','http://www.empf.org/empfasis/nav/images/empfasis_nav_02-over.gif','http://www.empf.org/empfasis/nav/images/empfasis_nav_03-over.gif','http://www.empf.org/empfasis/nav/images/empfasis_nav_04-over.gif','http://www.empf.org/empfasis/nav/images/empfasis_nav_05-over.gif','http://www.empf.org/empfasis/nav/images/empfasis_nav_06-over.gif','../../nav/images/empfasis_nav_01-over.gif','../../nav/images/empfasis_nav_02-over.gif','../../nav/images/empfasis_nav_03-over.gif','../../nav/images/empfasis_nav_04-over.gif','../../nav/images/empfasis_nav_05-over.gif','../../nav/images/empfasis_nav_06-over.gif')"> <table width="100%" border="0"> <tr> <td width="19%"><img src="http://www.empf.org/empfasis/archive/images/empfasis.jpg" width="360" height="71" border="0"></td> <td width="81%"><div align="right"><a href="http://www.empf.org" target="_parent"><img src="http://www.empf.org/empfasis/archive/images/empf.jpg" width="144" height="90" border="0"></a></div></td> </tr> </table> <div align="center"><!-- #BeginLibraryItem "/Library/empfasis_nav.lbi" --> <table border="0" cellpadding="0" cellspacing="0"> <tr> <td><a href="http://www.empf.org/empfasis/index.html" target="_top" onClick="MM_nbGroup('down','group1','empfasis','',1)" onMouseOver="MM_nbGroup('over','empfasis','../../nav/images/empfasis_nav_01-over.gif','',1)" onMouseOut="MM_nbGroup('out')"><img src="../../nav/images/empfasis_nav_01.gif" alt="" name="empfasis" width="64" height="34" border="0" onload=""></a></td> <td><a href="http://www.empf.org" target="_top" onClick="MM_nbGroup('down','group1','aci','',1)" onMouseOver="MM_nbGroup('over','aci','../../nav/images/empfasis_nav_02-over.gif','',1)" onMouseOut="MM_nbGroup('out')"><img src="../../nav/images/empfasis_nav_02.gif" alt="" name="aci" width="58" height="34" border="0" onload=""></a></td> <td><a href="http://www.aciusa.org" target="_top" onClick="MM_nbGroup('down','group1','empf','',1)" onMouseOver="MM_nbGroup('over','empf','../../nav/images/empfasis_nav_03-over.gif','',1)" onMouseOut="MM_nbGroup('out')"><img src="../../nav/images/empfasis_nav_03.gif" alt="" name="empf" width="48" height="34" border="0" onload=""></a></td> <td><a href="http://www.empf.org/empfasis/index.html#archive" target="_top" onClick="MM_nbGroup('down','group1','archive','',1)" onMouseOver="MM_nbGroup('over','archive','../../nav/images/empfasis_nav_04-over.gif','',1)" onMouseOut="MM_nbGroup('out')"><img src="../../nav/images/empfasis_nav_04.gif" alt="" name="archive" width="70" height="34" border="0" onload=""></a></td> <td><a href="http://store.aciusa.org" onClick="MM_nbGroup('down','group1','techpubs','',1)" onMouseOver="MM_nbGroup('over','techpubs','../../nav/images/empfasis_nav_05-over.gif','',1)" onMouseOut="MM_nbGroup('out')"><img src="../../nav/images/empfasis_nav_05.gif" alt="" name="techpubs" width="154" height="34" border="0" onload=""></a></td> <td><a href="mailto:empf@aciusa.org" target="_top" onClick="MM_nbGroup('down','group1','contact','',1)" onMouseOver="MM_nbGroup('over','contact','../../nav/images/empfasis_nav_06-over.gif','',1)" onMouseOut="MM_nbGroup('out')"><img src="../../nav/images/empfasis_nav_06.gif" alt="" name="contact" width="74" height="34" border="0" onload=""></a></td> </tr> </table> <!-- #EndLibraryItem --></div> <table width="100%" border="0"> <tr> <td width="85%" class="style17">A publication of the National Electronics Manufacturing Center of Excellence</td> <!-- InstanceBeginEditable name="Date" --><td width="15%"><div align="right">August 2010 </div></td> <!-- InstanceEndEditable --> </tr> </table> <table width="100%" border="0"> <tr> <td width="237" valign="top"> <div align="center"> <table width="237" height="1280" border="0" cellpadding="30" cellspacing="0"> <tr> <td width="237" valign="top" background="../../archive/images/left_banner4.jpg"><div id="lft_banner"> <table width="185" border="0" cellspacing="0" cellpadding="0"> <tr> <td><a href="http://www.aciusa.org" target="_blank"><img src="http://www.empf.org/empfasis/archive/images/aci_sm.gif" alt="Go to the ACI website" width="69" height="44" border="0" align="left" longdesc="http://www.aciusa.org"></a></td> <td><a href="http://www.empf.org" target="_blank"><img src="http://www.empf.org/empfasis/archive/images/empf_sm.gif" alt="Go to the EMPF website" width="65" height="44" border="0" align="right" longdesc="http://www.empf.org"></a></td> </tr> <tr> <td colspan="2"><div align="center"> <table width="175" border="0" align="center" cellpadding="0" cellspacing="0"> <tr> <td valign="top"><span class="style1"><span class="style24"><br> In This EMPFasis Issue<br> <br> </span></span></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_1" --> <p align="left"><a href="fuel.html">Fuel Cell Manufacturing Challenges</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top">&nbsp;</td> </tr> <tr> <td valign="top"><div align="left"></div></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_2" --> <p align="left"><a href="help-810.html">Ask the EMPF Helpline!</a> <!-- InstanceEndEditable --> </p></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_3" --> <p align="left"><a href="optimizing.html">Optimizing Fuel Cell Performance</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_4" --> <p align="left"><a href="tech-tips-810.html">Tech Tips: Microscopy in Failure Analysis</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_5" --> <p align="left"><a href="manf-corner-810.html">Manufacturer&rsquo;s Corner: McDry</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_6" --> <p align="left"><a href="electronics.html">Electronics Manufacturing Boot Camp Updates</a></p> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_7" --> <a href="http://store.aciusa.org">EMTC Online Registration</a> <!-- InstanceEndEditable --></td> </tr> <tr> <td valign="top"><p align="left">&nbsp;</p></td> </tr> <tr> <td valign="top" style="padding-left:10px"><!-- InstanceBeginEditable name="Article_8" --> <a href="../html/empfasis/emlcupcoming.pdf">Training Center Course Schedule</a> <!-- InstanceEndEditable --></td> </tr> </table> <br> <br> <hr align="center" size="1"> <br> <a href="http://store.aciusa.org"><img src="http://www.aciusa.org/images/lower-pricing-ad.gif" alt="Discount pricing on IPC training course J-STD-001, 610, 600, 7711, 7712" width="150" height="288" border="1"></a> <a href="http://www.empf.org/empfasis/subscribe.htm"> </a> <p class="style9"><script language="JavaScript"> <!-- function random_imglink(){ var myimages=new Array() myimages[1]="http://www.aciusa.org/wwwaci/html/random/boot.gif" myimages[2]="http://www.aciusa.org/wwwaci/html/random/lead.gif" myimages[3]="http://www.aciusa.org/wwwaci/html/random/help.gif" myimages[4]="http://www.aciusa.org/wwwaci/html/random/service.gif" myimages[5]="http://www.empf.org/empfasis/archive/images/subscribe2.gif" var imagelinks=new Array() imagelinks[1]="http://www.aciusa.org/courses/train_boot.htm" imagelinks[2]="http://www.empf.org/empfasis/leadfree.htm" imagelinks[3]="http://www.empf.org/helpline/helpline.htm" imagelinks[4]="http://www.aciusa.org/ana/ana_home.htm" imagelinks[5]="http://www.empf.org/empfasis/subscribe.htm" var ry=Math.floor(Math.random()*myimages.length) if (ry==0) ry=1 document.write('<a href='+'"'+imagelinks[ry]+'"'+'><img src="'+myimages[ry]+'" border=0></a>') } random_imglink() //--> </script></p> </div></td> </tr> <tr> <td colspan="2"><div align="center"><span class="style5">ACI Technologies Inc.</span><br> One International Plaza<br> Suite 600 <br> Philadelphia, PA 19113 <br> (610) 362-1200 <br> <span class="style6">FAX: </span>(610) 362-1290<br> <span class="style6">HELPLINE: </span>(610) 362-1320<br> <span class="style6">WEBSITE: </span><a href="http://www.empf.org">www.empf.org</a><br> <a href="http://www.aciusa.org">www.aciusa.org</a></div></td> </tr> </table> <p>&nbsp;</p> <p><br> <br> </p> <div align="center"> <p align="center" class="style7">Michael D. Frederickson<br> <strong><em>EMPF Director </em></strong><br> <br> Barry Thaler, PhD.<br> bthaler@aciusa.org <br> <strong><em>Empfasis Technical Editor<br> </em></strong><br> Paul Bratt<br> pbratt@aciusa.org <br> <strong><em>Empfasis Editor</em></strong><br> </p> <p align="center" class="style7"><img src="http://www.empf.org/empfasis/archive/images/iab_sm.gif" alt="IAB" width="100" height="52"><br> <span class="style9">Industrial Advisory Board</span><br> <span class="style14"><em>Gerald R. Aschoff</em>, The Boeing Company<br> <em>Dennis M. Kox</em>, Raytheon<br> <em>Gregory X. Krieger</em>, BAE Systems<br> <em>Edward A. Morris</em>, Lockheed Martin<br> <em>Jane Krueger </em>, Rockwell Collins<br> <em>Gary Kirchner</em>, Honeywell<br> <em>Andrew Paradise</em>, Northrop Grumman<br> <em>Richard Kidwell </em>, ITT Industries</span></p> </div> <p align="center" class="style7"><br> </p> </div> </td> </tr> </table> </div></td> <!-- InstanceBeginEditable name="Body1" --><td width="70%" rowspan="2" valign="top"><div class="body_style" id="body_content"> <p><img src="images/tech-tips.gif" alt="title"></p> <p class="body_text"><span class="style20">B</span>oth optical and scanning electron microscopy (SEM) are powerful tools for failure analysis in electronics and are used for low and high magnification examination. This article will provide detailed, step by step information for examining solder joints.</p> <p>Before using the high magnification of the SEM, a traditional optical microscope or an inverted optical microscope is used to locate your area of interest. For most external inspections, optical microscopes are useful to locate any obvious defects or anomalies on boards and components. For internal inspections, the sample can be cross-sectioned (or"microsectioned") to reveal layer by layer structure of a component on a printed wiring board (outlined in a previous Tech Tips article ---- Empfasis, April 2008). The optical image provides a road map for navigating your sample in the SEM.</p> <p>Step 1: Using an inverted optical microscope, examine the cross-section of the sample. Place the sample face-down on the stage (Figure 4-1). Use the x and y-axes controllers to move your area of interest to the center of the optical field (Figure 4-2).</p> <p>Step 2: To examine under a scanning electron microscope, samples must be made conductive. A sputter coater is used to deposit a thin conductive layer of gold on non-conductive samples (Figure 4-3).</p> <p>Step 3: After sputter coating, a conductive copper adhesive tape is used to bleed off any electron charge that may build up on the sample surface. Notice the metallic reflection from the surface that has been sputter coated with gold (Figure 4-4).</p> <p>Step 4: Place the sample in holder and secure with screw. Align the screw with the copper adhesive tape for grounding purposes (Figure 4-5).</p> <p>Step 5: Secure the holder on the stage of the SEM sample chamber and center the stage (Figure 4-6). Evacuate the sample chamber and wait until it reaches the required high vacuum level.</p> <p align="center"><img src="images/fig4-1.gif"></p> <p>Besides providing a greater magnification, a scanning electron microscope can be used to obtain elemental information from the sample. Backscattered electrons can be used to detect different chemical compositions in the sample. Heavier elements (higher atomic number) in the sample are able to backscatter electrons more than lighter elements and appear brighter in the image. In addition, characteristic X-rays are emitted when the electron beam interacts with the sample (energy dispersive X-ray spectroscopy or EDS). This provides information on elemental quantity and composition of the sample.</p> <p>Step 6: After reaching high vacuum, open the valve between the electron gun and sample chamber. In this sample, a solder joint of eutectic tin-lead (Sn63-Pb37) is being examined. The tin phase appears gray and the lead phase appears white. The bottom black portion is the copper phase from the board surface mount pad. Dark gray denotes the tin-copper intermetallic layer. Using EDS, the chemical composition of the sample can be determined at a specific location (indicated by the red cross in Figure 4-7). In this sample, the intermetallic layer between the solder and the copper contains 59% tin, 36% copper, and 5% lead by weight.</p> <p align="center"><img src="images/fig4-7.gif"></p> <p>The EMPF has the capability and experience to perform both optical and scanning electron microscopy for failure analysis. If you would like additional information, please contact the Helpline at 610.362.1320 or log onto the EMPF website at www.empf.org.</p> <p class="body_text"><img src="../../archive/updated/pyu.gif"></p> </div> </td> <!-- InstanceEndEditable --> </tr> <tr> </tr> </table> <br> <table width="100%" border="0"> <tr> <td colspan="2"><div align="center"> <p><em>The EMPF is a U.S. Navy-sponsored National Electronics Manufacturing Center of Excellence focused on the development,<br> application, and transfer of new electronics manufacturing technology by partnering with industry,<br> academia, and government centers and laboratories in the U.S</em></p> </div></td> </tr> <tr> <td class="footer">ACI Technologies, Inc. - - <a href="http://www.aciusa.org">www.aciusa.org</a> - - (610)362-1200</td> <td><div align="right"><a href="http://www.navymantech.com"><img src="http://www.empf.org/empfasis/archive/images/mantech.gif" width="144" height="42" border="0"></a></div></td> </tr> </table> <div align="right"> <!-- Start of StatCounter Code --> <script type="text/javascript" language="javascript"> var sc_project=350643; var sc_partition=1; </script> <script type="text/javascript" language="javascript" src="http://www.statcounter.com/counter/counter.js"></script> <noscript> <a href="http://www.statcounter.com/free_hit_counter.html" target="_blank"><img src="http://c2.statcounter.com/counter.php?sc_project=350643&amp;amp;java=0" alt="hit counter" border="0"></a> </noscript> <a href="http://www.empf.org/sitemap.htm"><em>[site map] </em></a> <!-- End of StatCounter Code --> <!-- Start of StatCounter Code --> <script type="text/javascript" language="javascript"> var sc_project=1902214; var sc_invisible=1; var sc_partition=17; var sc_security="759b802c"; </script> <script type="text/javascript" language="javascript" src="http://www.statcounter.com/counter/counter.js"></script><noscript><a href="http://www.statcounter.com/" target="_blank"><img src="http://c18.statcounter.com/counter.php?sc_project=1902214&java=0&security=759b802c&invisible=1" alt="website statistics" border="0"></a> </noscript> <!-- End of StatCounter Code --> </div> </body> <!-- InstanceEnd --></html>