Advances in X-Ray Technology for Semicon Applications Keith Bryant and Thorsten Rother X-Ray Champions, Telspec, Yxlon International
Agenda The x-ray tube, the heart of the system Advances in digital detectors Enhancing the image and automation Advances in computed tomography Challenges of microelectronics applications
Introduction X-Ray Technology has been around for over 100 years mostly in the Medical industry Traditionally Electronics used components from Medical Systems FeinFocus was the first X-Ray company in the Electronics industry in the 1980s. Most companies came from here
The x-ray tube, the heart of any system Most systems for electronics applications use Open transmission tubes, this technology is 55 years old Open tube technology has improved dramatically in all key areas over the last 10 years
Recent Advances in Open Tube Technology Pre-vacuum pumps are maintenance free Vacuum inside the tube is much higher improving feature recognition Filament lifetime has been extended some 4 times Replacement of the filament can now be done in a few minutes, as a pre-adjusted quick change unit can be clicked into place, fast and easy
Recent Advances in Open Tube Technology Modern high end x-ray systems include the following features and settings: Multifocus x-ray capability for more flexibility New types of targets, for demanding applications True X-ray Intensity (TXI) control for stable and repeatable imaging results
Multifocus x-ray capability Nanofocus Semi-conductor Applications < 0.3µm Feature Recognition Microfocus Assembly Applications < 1µm Feature Recognition High Power High Density & Optoelectronics < 3µm Feature Recognition
New types of targets Open tube design allows the use of dedicated targets, developed specifically for demanding applications High Power target (diamond based) High Resolution Power target (diamond based) High Magnification target Conical target
True X-ray Intensity (TXI) control Target current is measured continuously Emission current is adjusted automatically Without TXI Benefits include: Consistent results over time Accurate void measurements Better image quality of CT scans With TXI
Nanofocus Mode with HPR target X-ray Image of a solder crack in 50μm Cu pillar, Sample size: 300mm wafer X-ray Image of a polymer material, voids and orientation of fibers are easily visible
TXI + High Power Resolution target CT scan of a failed Multi-Layer Ceramic Capacitor TXI technology secures extremely stable image quality for each projection High Power Resolution target allows the use of a high target power without decreasing the resolution
The Detector, the art of the image Early technology was Analogue using lens s and a camera Image Intensifiers then improved using software and better camera technology The Digital Flat Panel was a huge leap forwards, from 0.3 MPixels to 1 MPixels Now DFP s are available, designed and purpose built for our industry
High End Flat Panel Detector Technology Real-time Imaging Distortion-free Image High-contrast and highly detailed image 16 Bit Image processing for great greyscale (65000 shades) UHD flat-panel detector image of µbga
Recent Advances of Flat Panel Technology Panels are now less sensitive to radiation so their lifetime is extended Frame capture rate is faster so good images are on screen sooner Pixel size is reduced to make it easier to see smaller features at high magnification
High Quality Real Time Digital Imaging
Enhancing the image chain The biggest recent improvement has been in special filters which dramatically improve the on-screen image Benefits: Faster inspection Easier to see faults Less operator stress μhdr live filter
Automation has to be accurate and repeatable 17 micron gold wires
Automated wire sweep measurement red indicates failure
Computed Tomography Advances Advanced x-ray systems provide fast scanning QuickScan delivers almost as good result but much faster, in 3 to 5 minutes versus more than 30 minutes Conventional µct (left) and QuickScan (right) of a BGA with volume views (top) and views of a slice (bottom)
QuickScan Plus HPR x-ray tube target TXI (True Intensity Control) 10-15W target power Real Time Flat Panel Detector 64bit CT High Speed reconstruction software QuickScan Plus - volume view and virtual cross-sections of micro-bga with micro-vias, wedge bonding
Cracked Passive caused by interfacial voiding
Challenges of Microelectronics As component engineers escalate from 2D single die designs to 3D multiple die package solutions, it sets high demands for inspection tools.
Challenges of Microelectronics Thinned die cracking Stacked packages must be able to maintain the Z-height of a standard package, requiring thinned die down to 50μm Thinned dies make stacked components susceptible to brittle fracture failures Die cracking is a significant concern with stacked packages Die cracking Cracked die
Challenges of Microelectronics Flip chip connections In most current 3D packages, the stacked chips are connected along their edges with wire bonds Also flip chip bumps are used to create an interconnection between stacked dies Potential defects of flip-chip bumping opens and solder voiding Flip-chip pin grid array, FCPGA Flip chip bump area voiding
Challenges of Microelectronics Thru Silicon Via (TSV) connections TSV replaces edge wiring by creating vertical connections through the body of the chips A TSV is a via hole in a silicon wafer, which is insulated and filled with a conductive fill, usually copper Micro void in 30μm diameter TSV
Head on Pillow, 30µm µbga balls chip structure easily visible
35µm µbga ball with voiding and open circuit (HoP)
25µm diameter copper pillars 50µm long, 2D angled view
2D angled view of 20µm TSV µbumps
Voiding measurement of 15µm copper pillar
3D image of 6µm diameter TSV s
25µm Copper Pillars and 6µm TSV µbump connections
Automated measurement of blind and buried µvias
Thanks for your Attention Any Questions?