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Multiple Patterns, Multiple Trade-Offs

As the saying goes, “There is no such thing as a free lunch.” That is a reality that chip designers have had to live by from the beginning. From the advent of the first design rule, it was clear that you couldn’t just do anything you wanted. In the end, everything comes down to trade-offs. Whether it’s area, speed, leakage, noise sensitivity, or drive current, doing something to impr... » read more



Is Multi-Patterning Good for You?

I think we can all remember growing up and our parents making us take nasty-tasting medicines, or eat foods we didn’t like, or endure painful things like shots, all under the banner of “It is good for you!” We didn’t like it then, and we still don’t like it as adults. We would all prefer a way to lose weight while eating anything we want, or building strong muscles and aerobic health ... » read more



Self-Aligned Double Patterning—Part Deux

In my last article, I introduced you to the basic Self-Aligned Double-Patterning (SADP) process that is one of the potential candidate techniques for processing metal layers at 10nm and below, but let’s have a quick recap. SADP uses a deposition and etch step process to create spacers surrounding a patterned shape (Figure 1). As you can see, there are two masking steps—the first mask is cal... » read more



Self-Aligned Double Patterning, Part One

I’m sure most of you have seen a Rorschach test ink blot (Figure 1). Psychiatrists ask the subjects to tell them what they “see” in the ink blot. The answers are used to characterize the respondent’s personality and emotional functioning. I am never sure if I would feel more uncertain being the psychiatrist asking the question, or the subject trying to decide what to say, given there ar... » read more



When Order Matters

Do you brush your teeth before dinner? Put on your shoes before going to bed? Iron your clothes before you wash them? Okay, forget that last one. No one irons clothes anymore…do they? Anyway, my point is, if you want to achieve the best results from a process, order can be really important. And so it is with double patterning (DP) error debugging. As I’ve discussed, there are many types ... » read more



The Trouble With Triples—Part 2

In my last blog, we started to look at some of the challenges of triple patterning (TP) compared to double patterning (DP). In particular, we looked at the algorithmic complexity of determining if a valid coloring solution exists, and if so, producing a three-mask decomposition. This time, let’s look into the challenges of what to do if a layout is not legally decomposable into three colors. ... » read more



The Trouble With Triples—Part 1

If you’re a true geek like me, you may remember the Star Trek episode “The Trouble with Tribbles,” about the cute furry little aliens that purr when you pet them. They seemed so nice and friendly on the surface, but in the end, they became an exponentially growing mass of ravenous monsters that almost broke down the ship and consumed the storehouse of grain that was meant to provide human... » read more



You Ain’t Seen Nothing Yet

I’ve been talking about double patterning for a long time now in this series of blogs. I thought it might be good to start looking ahead at what is next for multi-patterning (Don’t Panic!). As you may have been hearing or reading, it doesn’t look like EUV lithography is going to be ready for 10nm, and may not even make it for 7nm. This means that alternative methods of extending the exist... » read more



You Can’t Get There From Here

By David Abercrombie In my last article, I reviewed the aspects of cell design that are affected by double patterning (DP). This time, I’ll discuss how automatic routing is affected by DP. Let’s begin by looking at the interaction between decisions made at the cell design level and decisions made at the routing level. One key routing decision is whether or not you will allow cell-to-cel... » read more



Between A Rock And A Hard Place

By David Abercrombie My previous articles included a lot of discussion about correcting error violations in double patterning (DP). This time let’s take a step back up the design flow. DP requires a design team to make some important decisions about standard cell design methodologies, or risk running into serious placement issues down the line. Understanding why this is so, and what your opt... » read more



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