This article is a starting point on the subject of Memory. It touches all the memory types available in the market. Also, people who are looking for a career change or to learn something new will find this useful. In fact, there are a lot of opportunities to learn in this domain and one can even make a career in this domain.
In computing, memory refers to a device that is used to store information for immediate use in a computer. Memory can contain the data to be processed as well as the instructions of how the data must be processed.
Types of Memory
A typical chip has multiple blocks (CPU, Logic, DSP, Audio, Microcontroller, Bluetooth, Ethernet etc.). It highlights different types of on-chip memory. It is observed in most of the chips that more than 50% of chip area is memory. There are over 45 companies worldwide, which design these memory types. These memory types vary from few kilobits to a maximum few megabyte. Memory companies design these memories in different process technology nodes (example 45m, 32nm, 20nm, etc.) and fabricate it before offering a silicon proven memory to their customers. The basic memory cell that stores a single bit of data comprises of six transistor structure. This is the fastest memory available among all other types of memory available. Designing of this memory type involves schematic drawing, simulation, layout drawing, Physical verification checks, EMIR checks, ESD checks etc.
Off-Chip memory: DDR, LPDDR, GDDR, HBM
RAM is a common word that we use in day-to-day conversation while sharing the specs of a hardware. For example, we say, “My phone has 6 GB RAM, storage of 64GB, expandable up to 256 GB”. RAM stands for Random Access Memory. For the battery-operated devices, Low Power DDR standard has evolved and today, the industry is shipping LPDDR5 and LPDDR6. For GPU’s, GDDR and HBM was invented.
This memory comes in different forms, factors and different packaging options. A lot of opportunities exist in the domain of SI/PI.
Memory flow and Memory Tree
The memory flow and memory tree in the pictures show the hierarchy through which the processor gets access to the memory. As we go down the pyramid, the speed at which data can be exchanged with processor reduces. As we go down the pyramid, memory capacity goes up, and price per bit of the memory goes down.
Storage memory: HDD, SSD, SD
Storage memory options are available in different formats and in different capacity from several companies like Sandisk, Intel, Hynix etc. This memory is also called NAND based Flash memory.
New research in memory
A few companies are working on redefining the memory tree. There is an opportunity to create a layer between DRAM and SSD and this new type of memory will have a higher capacity than the DRAM and will have higher speeds than the SSD.
The industry is inventing new methods to integrate memory with the logic/processor die. Here are some examples of existing packaging architectures: chip on Wafer on Substrate (CoWoS), Wafer on Wafer (WoW), Integrated Fan Out (InFO), InFO-Package on Package (InFO-PoP), InFO-MS, etc. This area will continue to expand and will give opportunities to people willing to build career in this domain
Looking forward to this industry trend, there is a growing need for people to learn the art of simulating their design with multiphysics analysis. Ansys is leading in this domain and supporting multiple companies to be successful.
About the author: Himanshu Rawal ,Senior Enterprise Account Manager, Ansy
Himanshu Rawal, has worked with semiconductor companies for over 16 years in different roles. During these years, he interacted with groups for whom writing low power RTL, maximizing the verification coverage, Design for Manufacturability, maximizing Yield, Electro-migration, ESD checks, Physical verification was important. He holds a B.E degree from Maharishi Dayanand University and has completed his M.Tech from Manipal Institute of Technology.