As the tug-of-war between efficiency and security unfolds, stacked die are on the front lines. The Internet of Things is requiring faster performance and reduced power requirements, along with a focus on efficient and compact solutions. Stacked die are an innovation which satisfy those requirements. But the potential security risks introduced by single package stacks of chips exposes the flip side of our current efforts. Can stacked die be made secure and replace the planar packages? Or is it just a matter of time before a security breach makes stacked die another failed technology of the past?
Benefits of Stacked Die
Setting aside the potential lower costs of a stacked die, there are a number of functional and practical benefits of the technology. Initially, the vertical through-silicon pipelines or vias allow for vertical communication between chips of different kinds. This third dimension technology, or 2.5D architecture, allows for stacked DRAM, flash memory, a WiFi radio, and a processor all in one block.
The efficiency of production could be huge, but so will the efficiency of power consumption and the potential speed increase. Of course, this technology also allows for the size of the entire set of possible chips to be smaller.
Stacked Die Vulnerabilities
The fear, and it’s not an entirely unfounded fear, is that the increased complexity leaves room for security breaches. A stack of ICs is harder to control than single chips laid out individually. Malicious circuitry could be introduced in a way wouldn’t become apparent until well after the stacked die are in use. Counterfeit chips, malicious IP blocks, or capability commands are all potential problems for stacked die manufacturers and users.
But just like any new technology, a lot of the fear is around unknown factors and a lack of security development so far. As we continue to explore the benefits of stacked die technology, we can limit threats and begin to integrate security protocols which deal with the identified potential problems. The supposed vulnerability of stacked die also allow for unique security engineering ideas and solutions which may be more secure in the long run than after market solutions.
Controlling for human error and creating a groundwork of security will help ensure that stacked die live up to their potential. As the Internet of Things extends and grows, a solution like stacked die is just what we need.