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One-On-One: Dark Silicon


Professor Michael Taylor’s research group at UC San Diego is studying ways to exploit dark silicon to optimize circuit designs for energy efficiency. He spoke with Semiconductor Engineering about the post-Dennard scaling regime, energy efficiency from integrated circuits all the way up to data centers, and how the manufacturing side can help. What follows are excerpts of that conversation. (F... » read more

DSA Defects Continue Downward Trend


As previously discussed, the majority of defects in early directed self-assembly (DSA) processes were due to particles and other contaminants, and could be attributed to the immaturity of the process and materials. As manufacturers consider whether to incorporate DSA into specific technology nodes, they need to assure themselves that production-worthy yields can be achieved. Recent research at ... » read more

How To Deal With Electromigration


The replacement of aluminum with copper interconnect wiring, first demonstrated by IBM in 1997, brought the integrated circuit industry substantial improvements in both resistance to electromigration and line conductivity. Copper is both a better and more stable conductor than aluminum. Difficult though the transition was, it helped extend device scaling for another eighteen years (and counting... » read more

Tighter CD Requires Tighter Laser Bandwidth


Concerns that the bandwidth of the light source for optical lithography can affect pattern quality are not new. No lens material is completely free from chromatic aberration: the refractive index varies with wavelength, and so different wavelengths will focus at different points. Chromatic aberration became a much less serious concern with the replacement of broadband mercury lamps with lase... » read more

Talking About Dark Silicon


Back in January, my article on dark silicon referenced work done by Michael Taylor and his research group at UC San Diego. I wasn’t able to arrange an interview with Dr. Taylor in time for that article, but we did have an extended conversation earlier this week. He pointed out that, while further decreases in threshold voltage are constrained by device leakage, the energy consumed by a circui... » read more

Darker Silicon


For the last several decades, integrated circuit manufacturers have focused their efforts on [getkc id="74" comment="Moore's Law"], increasing transistor density at constant cost. For much of that time, Dennard’s Law also held: As the dimensions of a device go down, so does power consumption. Smaller transistors ran faster, used less power, and cost less. As most readers already know, howe... » read more

Integrating DSA


As previous articles in this series have shown, directed self-assembly may be a promising alternative for manufacturers seeking to shrink feature sizes in the face of a stalled exposure tool roadmap. It is simpler than some other frequency-multiplication techniques, can be implemented with existing equipment, and does not appear to introduce insurmountable defect issues of its own. Which does n... » read more

DSA Moves Ahead


It can be difficult to make DSA structures other than uniform arrays. One solution is to print a grating over a large area, then use a “cut” mask to eliminate the unwanted features. The challenge, though, is that aligning the cut mask to an array of tightly spaced features, such as the fins for a FinFET transistor layer, can require extremely demanding overlay specifications. While reducing... » read more

Counting And Controlling DSA Defects


If directed self-assembly is to succeed in semiconductor manufacturing, [gettech id="31046" t_name="DSA"] processes must achieve defect rates in line with the stringent requirements of sub-20nm device nodes. So far, they haven’t. However, it’s not yet clear whether the high defect rates represent a real obstacle, or are simply part of the development of any new, immature process technology... » read more

The Key To DSA


The block co-polymer most commonly used in directed self-assembly research ([gettech id="31046" t_name="DSA"]), PS-b-PMMA (poly(styrene-block-methyl methacrylate) is an excellent choice because the two component monomers have similar surface energies. The exposed top surface of the film helps to stabilize the segregated domains, making it relatively easy to achieve the lamellar line-and-space p... » read more

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