Memory Module Manufacturing Part 4
Once memory chips are made, we still need a way to connect them to your computer. To do this, the chips are mounted to printed circuit boards (PCBs). The final assembled product is called a memory module.
Micron engineers design memory modules using Computer Aided Design (CAD) programs. Module sizes will vary depending on the chip's configuration (SIMM, DIMM, Memory type, etc.). Chip configuration also determines the electrical characteristics of the PCB.
The PCB is a critical part of the memory module. It enables your computer to access the memory. For this reason, Micron engineers place significant effort on correctly designing the PCB. Each design is tested by simulation and undergoes multiple design improvements prior to release for production.
PCBs are built in arrays, or sheets, made up of several identical boards.
After assembly, the array will be separated into individual modules, similar to how a chocolate bar can be broken into small squares. By varying the total number of PCBs in each array based on size, Micron maximizes the number of modules made from a given amount of raw materials. The Micron Design Engineering group also interacts frequently with system manufacturers' engineers to optimize the design process and improve manufacturability of the customer's modules.
When the module design is perfected and the PCBs produced, memory module assembly begins! Assembly entails an intricate soldering procedure that attaches memory chips to the PCB.
Throughout the entire module assembly process, Micron takes great precaution to eliminate electrostatic discharge (ESD), or what most of us refer to as static electricity. ESD damage is a leading cause of device failure. That same "shock" you feel after shuffling your feet across carpet then touching something can completely destroy a memory chip. In fact, a person passing within 12 inches of an unprotected chip can cause damage. Micron team members wear protective clothing and use anti-static equipment during the assembly process. This ensures that any electrical charges on people or equipment will not transfer to the memory modules. Additionally, after every manufacturing step, the product is checked and verified and in-line Statistical Process Control (SPC) data is gathered. These checks provide immediate feedback to ensure continuous improvement.