What do you do when the worst Nightmare hits? That’s a question that 3D Plus faced when the 8Gigabit DDR3 x32 DRAM component it was using for avionic and aerospace applications was discontinued. Normally, a discontinuation is not a big deal. The application system manufacturer upgrades its design to incorporate the product of a different vendor that often has been pre-qualified or moves to a newer technology generation.
3D Plus approached the memory competence center MEMPHIS Electronic in the hope that one of the 18 memory manufacturers in its line card would still have the product. With its expertise in memory for industrial uses Memphis has already helped 3D Plus out a couple of times. However, the 8Gb DDR3 x32 was a rare product that only a few manufacturers had provided in the first place, and the x32 option had been discontinued by all of them because the volumes sold were just too low.
The obvious alternatives of moving to a new DRAM generation or using two individual 4G DDR3 x16 chips in a single package weren’t an option. In this case, a qualified design that has been approved cannot be changed which is common in certain industries like medical or avionic.
When impossible is not in your vocabulary
That’s when the strength of the memory powerhouse Neumonda came into play that MEMPHIS Electronic is part of. Part of the group is also the memory IP division called Neumonda Technology which focuses on the development of DRAM components and DRAM test kits. It developed a new prototype of a lightweight DRAM tester that has been designed to conduct vendor-independent tests that also simulate the actual environment in which the DRAM memory is going to be used. With this new approach, it’s not only possible to predict potential failures much more accurately, but also tell how well a DRAM will actually do in the specific environment. All this at a fraction of the costs of traditional testers.
MEMPHIS introduced 3D Plus to Neumonda Technology and the two companies discussed the exact needs for this project. The team reviewed the requirements with the specialist memory manufacturer Intelligent Memory, the third company in the Neumonda Group, and the IM team was confident it could manufacture the components that 3D Plus needed. Neumonda Technology then took on the task of testing and qualifying the DRAMs with the prototype of its new Rhinoe Tester, so they would meet the specific requirements of an extended temperature range of -40° to +105° Celsius.
Improved Test Flow
For the testing process, the DRAMs were placed in the sockets of the test board and then Neumonda’s own test software ran the various tests ranging from burn-in via memory array speed to interface speed tests at wide temperature ranges with the help of a micro-climate chamber. A security guard band was applied to ensure increased retention time and allow for overclocking frequencies. All this testing is conducted without having to unload the DRAMs in a new test platform at the risk of damaging the ball pins.
With this radically new approach, and due to the small size of the tester, the factory flow of testing could be altered. There is no need to move the memory components to the stationary test equipment which often weighs several tons. Contrarily it should be the small and lightweight tester loaded with memory components that moves through the factory. The components simply needed to be loaded onto the tester board once and stayed connected during the entire production flow while all processing steps were executed.
In conventional memory testing, components are loaded and unloaded up to seven times for the different test steps to be executed such as burn-in, array-test and speed test at various temperatures. The process of loading and unloading can potentially damage the package balls and is prone to accidentally mixing up semiconductor components during this traditional test flow.
The tests that the Rhinoe tester runs are based on Neumonda patented IP which does not require any wafer-related IP or insights into the proprietary test modes of the memory manufacturer.
High-Quality Result
The prototype of the tester proved its value to the customer: Over a period of three years, there were no customer returns which underlines the good quality of the DDR3 memory components that Intelligent Memory manufactured that even exceeded the requirements of the customer. This was thanks to Neumonda Technology being able to simulate the actual application environment in which the product would be used in during its testing.
The prototype in the meantime was transformed into today’s Rhinoe tester platform which won an Elektra Award in November 2023. With this unusual approach, MEMPHIS Electronic was able to satisfy the customer by combining the strengths in memory know-how and supply chain with memory manufacturing and an innovative approach to memory testing, a competency that is unmatched in the market.
Author: Marco Mezger, COO of NEUMONDA and President of MEMPHIS Electronic