Issue link: https://iconnect007.uberflip.com/i/322206
72 SMT Magazine • June 2014 age close to 100%. And the higher the percent- age of BGAs, the higher the importance of these technologies. In today's situation, they seem to be the only solution for HDI assemblies. Figure 13 illustrates a possible production line for that situation. The basic idea is, to install a sensor after each production process and to feedback statistical fault information to all process steps. Due to its high inspection speed, the AXOI system can qualify the assembly according to IPC-A-610E and measure, for example, the inner solder me- niscus of TQFP components. The still missing mechanical fault coverage will be ensured by the integrated AOI system. The MXI machine is used for high precision analyses. Summary and Conclusions BGA components are an important part of complex board assemblies. They permit ever higher densities and improvements of electri- cal parameters. The steadily decreasing node access enforces appropriate countermeasures to be taken in the form of alternate inspection and test methods. In practice, particularly 3D AXOI machines (combined AXI/AOI systems) plus electrical Boundary Scan test methods have the greatest potential to solve those access issues. Both methods complement each other perfect- ly and permit a fault coverage for BGA solder joints of almost 100%. Furthermore, boundary scan has a fundamental future proofness, as it is based on progressive IEEE standardisation ac- tivities [9] [10] . Remember, the optimal use of the discussed system solutions requires a thorough analysis of the entire process. SMT References 1. IEEE Std.1149.1-2013, Standard Test Ac- cess Port and Boundary Scan Architecture. 2. Std. IPC-A-610, Acceptability of Electron- ic Assemblies. 3. Std. ANSI/IPC-7095-2000, Design and As- sembly Process Implementations for BGA. 4. Produktinformation OptiCon X-Line 3D, GOEPEL electronic, 2013. 5. Produktinformation ScopeLine MX-1000, GOEPEL electronic, 2014. 6. Produktinformation Softwareplattform SYSTEM CASCON™, GOEPEL electronic, 2014. 7. Produktinformation Hardwareplattform SCANFLEX ® , GOEPEL electronic, 2013. 8. Produktinformation PicoTAP Designer Studio, GOEPEL electronic, 2013. 9. IEEE Std. 1149.6-2003, Standard for Boundary Scan Testing of Advanced Digital Networks 10. IEEE Std. P1149.8.1, Standard for Bound- ary Scan based Stimulus of Interconnections to Passive and/or active Interconnections. 11. Thomas Wenzel/Heiko Ehrenberg—Der Paradigmenwechsel beim elektrischen Test, White Paper, GOEPEL electronic, 2012. THe TROuBLe WITH BgA SOLDeR JOInTS continues arTICLe figure 13: example of the use of aXoI, MXI and boundary scan in a bGa assembly line. Thomas wenzel is the managing director of the boundary Scan division of goepel. he can be reached at t.wenzel@goepel.com. andreas Türk is the head of automated X-ray inspection at goepel. he can be reached at a.tuerk@goepel.com.