In an effort to reduce the cost-of-test (COT), a number of customers are increasing the parallelism of logic wafer probe cards. However, due to the complexity such as pitch and number of probes, the pricing for these cards is reaching astronomical levels. We do not believe this trend is sustainable, let alone logical. The presentation suggested examples of alternative solutions. It is clear that critical solutions need to be optimized at the test cell, factory, and supply chain level not just at the consumable (probe card) level.
For the last fifteen years the International Technology Roadmap for Semiconductors (ITRS) has been looking fifteen years into the future. Based upon technology requirements and other inputs, ranging from the gate size of transistors to advanced packaging technology, the Test and Test Equipment Technical Working Group (Test TWG) has worked to develop the requirements for test technology and equipment.
The Test TWG is over seventy volunteers with deep technical expertise in test from around the world and from every sized company – Fortune 100 to individual consultants – and every type of company – semiconductor independent device manufacturer (IDM), fabless semiconductor, foundry, outsourced assembly and test (OSAT), automated test equipment (ATE) suppliers, prober, probe card, socket, handler, and more. Through Continue reading “IEEE Semiconductor Wafer Test Workshop 2014 Presentation”
Integrated circuits using 2.5D advanced packaging are shipping. 3D packaging with thru-silicon vias (TSV) has been demonstrated. “5.5D” packages may not be far behind. Probe card suppliers have made progress building interconnect technology for the micro-bump arrays. Standards committees have started defining IC interface standards and test access protocols.
But what does the Test Engineer and Management really want? What can they afford? What are the most likely scenarios? Factors that determine which test technology can support the desired test flow are examined. In particular, probe card technology for probing TSV bumps and potential usage models are reviewed.
Rob Marcelis (BE Precision Technology ‐ The Netherlands), “H3D Profiler for Contact Less Probe‐Card Inspection”:
Probe cards require inspection since they are consumables subject to wear. Changes in probe position or shape can damage the semiconductor devices they are testing. As probe cards increase in size and probe count, the probe cards themselves are becoming more expensive to test in terms of test time and complexity. Each new test system typically requires an expensive “motherboard” for the probe card metrology tool to simulate the mechanics of the tester and provide electrical interconnect to the card for electrical testing.
Jose Horas (Intel Mobile Communications ‐ Germany), “28nm Mobile SoC Copper Pillar Probing Study”:
Intel Mobile Communications (IMC, previously Infineon Wireless) has started to switch from tin-silver (SnAg) solder bumps to copper pillars (CuP) with SnAg caps for attaching their die to packages. Since the bumps and pillars are formed on the wafer prior to testing of the devices the wafer probe process must accommodate both. CuP offer several advantages over SnAg bumps: tighter pitch (now at 120 µm and able to scale smaller versus 150 µm for SnAg bumps), lower substrate costs due to relaxed design rules, and lower assembly costs (easier to under fill).