SEMulator3D News

Intel Announces Production-Ready 22nm 3-D Tri-Gate Transistor

Yesterday Intel announced its readiness for high-volume manufacturing of 3-D tri-gate (FinFET) transistors.  Among other benefits, the tri-gate configuration allows Intel to manufacture higher performance fully-depleted devices without resorting to Silicon-On-Insulator (SOI) wafers.  The performance gains quoted by Intel over their own 32nm planar transistor technology are impressive, including a 37% speed increase at low voltage , 18% speed increase at high voltage and 50% or greater power reduction at constant performance.  All these performance benefits come with only a 2-3% cost increase.

The shift to tri-gate transistors is a major architectural and conceptual shift from standard planar transistors.  Due to the non-planar nature of the devices, process integration challenges in producing such a device are considerable.  SEMulator3D is well placed to help process integration engineers understand and surmount manufacturing challenges for advanced FinFET devices, as demonstrated with the 32nm FinFET models that are available on our application examples page.

SEMulator3D is used for process development/integration, as well as documentation and communication about complex processes and for technology transfer.  More information about how and why to use SEMulator3D can be found on Coventor’s SEMulator3D website.

 

SEM image and information about Intel transistors are courtesy of Intel Corporation.

SEMulator3D is a registered trademark of Coventor, Inc.

Process Simulation vs. Process Emulation: is SEMulator3D really TCAD?

I was interested to note that Silvaco has recently listed SEMulator3D as a competitor for their VICTORY Process Cell software on their website. It’s great to be mentioned as a contender in the TCAD process simulation space. But I’d like to take the opportunity to examine the following question – are SEMulator3D and VICTORY Process Cell really direct competitors?

On the surface, both SEMulator3D and VICTORY Process Cell can do some similar things.  Both tools are fast, layout driven process modeling engines that are designed to build 3D models of MEMS and semiconductor devices. Both tools can model individual process steps or entire process sequences, and can model a variety of process and device types. And both tools can create meshes suitable for further physics simulation.

 

Figure 1: A 3D MEMS Actuator, fabricated using the SCREAM process [1]. Left - Silvaco Process Cell (image is from the Silvaco website and is the property of Silvaco). Right - SEMulator3D.

But despite the superficial similarities, there is an important distinction to be made between process simulation and process emulation. Process Cell and its direct competitors (Synopsys Sentaurus Process and similar) are process simulation tools and are based on TCAD simulation technology. The word “simulation” is key here because these tools simulate process steps using physical process models, driven by physical input parameters (implant energies, etch times and temperatures, etc). The models generated by these tools are well suited for detailed simulation of transistor electrical performance. But due to the complexity of the models, the chip area that can be modeled is relatively small – usually a single transistor, or at most a single layout cell. And because of their TCAD heritage, process simulation tools are often driven by a scripting language (powerful but can be difficult to learn).

SEMulator3D, on the other hand, is a process emulation tool.  SEMulator3D creates models of process steps using geometric parameters – parameters that describe the shape, thickness, or depth of individual processing steps. While not as fundamental as physical parameters, geometric parameters are easier to determine (for example, can be extracted from a SEM of a device). SEMulator3D is driven by an easy to use graphical interface, freeing users to think about processing issues rather than script syntax. And SEMulator3D is uniquely capable of modeling large areas of silicon, measured in microns rather than nanometers.

Figure 2: A MEMS threshold accelerometer, fabricated using a dissolved wafer process and Silicon/glass wafer boding [2]. SEM image reproduced with permission of the author (Arjun Selvakumar). On the right is a SEMulator3D model.

So what does this all mean? From my perspective, it means that both process simulation and emulation are useful, but for different tasks.

3D process simulation (TCAD) is ideally suited for detailed device simulation – and for detailed electrical performance simulation - of individual devices or perhaps single cells.

In contrast, 3D process emulation (SEMulator3D) is ideally suited for fast 3D model generation, visualization, process/layout verification, and especially communication. Since SEMulator3D is fast and easy to use, it’s a great way to communicate about processing topics within the fab. Process engineers and integration teams can save wafers by validating their process and layout before fabbing. And since SEMulator3D supports document creation in a number of standard formats, it’s a great tool for process documentation.

So when you look at these two tools in a bit more detail, they are really quite different. Both are useful and capable, but in different ways. Perhaps both tools will find a niche in the process development cycle and combine to make process development more efficient and profitable.

More information about SEMulator3D is available on the main SEMulator3D web page.

Silvaco VICTORY Process Cell and Synopsys Sentaurus Process are the trademarks of their respective owners.

References:

[1] MacDonald N, 1996 "SCREAM MicroElectromechanical Systems", Microelectronic Engineering 32 49-73.

[2] Selvakumar A,Yazdi N, Najafi K, 2001 "A wide-range micromachined threshold accelerometer array and interface circuit", J. Micromech. Microeng. 11 118-125.

3-D Process Modeling - A Novel and Efficient Tool for MEMS Foundry Design Support

Abstract – In this paper (click here to download) we describe a novel tool for modeling the fabrication of MEMS and semiconductor devices, and show some examples of its application in the MEMS foundry business. The tool allows an accurate visualization of the step-by step creation of the final 3-D device geometry by using the 2-D layout and a description of the fabrication process. The novelty of the tool lies in its use of voxels (3-D pixels) rather than conventional 3-D CAD techniques to represent the 3-D geometry. The tool creates highly realistic, 3-D virtual prototypes of micro-fabricated devices. Examination of these virtual prototypes can reveal design errors as well as the impact of design changes and process variations before each mask tape out and fab run, potentially reducing or eliminating design-fabricate- test cycles. To demonstrate the value of this tool to a foundry, the paper describes how the tool has been applied to a MEMS SOI micromachining process. Two detailed case studies are provided: a 3-D design check that revealed a design flaw before fabrication, and an analysis of a process failure which confirmed the suspected cause of undesired pocket-like cavities on the edges of silicon structures.

Virtual fabrication is a more productive way to build integrated MEMS/CMOS systems than process simulation.

by:Maurice J.A. Delafosse is MEMS product engineer, DPFS department, at Dalsa Corp. in Bromont, Canada. 

Gerold Schröpfer is director of European operations and foundry partner program for Coventor in Sarl Paris, France. 

Dalsa Semiconductor and Coventor have published an article on the use of virtual fabrication for MEMS processing. Virtual fabrication process emulation backed up by experimental calibration is a more productive way to build integrated MEMS and CMOS systems than process simulation. It provides a link between fab and design, is a lower-cost and faster technique, and provides a unique method to understand and improve design and process interaction, and wafer control/inspection. It leverages the enormous knowledge and tooling that has been developed in CMOS semiconductor fabrication, and transfers that knowledge to the MEMS world. --> read more

(left) SEM image and (right) SEMulator3D image of process steps in the Dalsa MEMS process.

X-Fab and Coventor present paper at SemiconWest on MEMS fabrication

3-D Process Modeling - A Novel and Efficient Tool for MEMS Foundry Design Support.
We describe a software tool for creating highly realistic, 3-D virtual prototypes of MEMS and semiconductor devices, and show how it has been applied to a MEMS SOI micromachining process. Two case studies demonstrate the value of virtual prototypes to a foundry: a 3-D design rule check that revealed a design error before mask tape out, and a process integration analysis that confirmed the suspected cause of a process failure.

Download presentation

Process emulation techniques are a great way to get 3D models and they are faster to build than simulated models.

Geometric emulation of MEMS Technology. This approach utilizes a geometric description of the result of each process step that is concatenated to build a geometric model of teh complete MEMS device. The geometric emulation approach has become a widely accepted approach for MEMS visualization applications. Koppelman first utilized geometric emulation in the OYSTER program, which was subsequently extended to the MEMBuilder and MEMulator modules incorporated into the CoventorWare software. The geometric emulation approach is capable of modeling the spectrum of process steps (i.e., conformal depositions, planarization, etch profiles, gap fills, etc.) encountered in MEMS processes in a computatially efficient manner, thus providing the MEMS designer with meaningful information.
Micro Electro Mechanical System Design by James Allen. CRC press, Taylor and Francis. page 185.

 

 

 

MEMS Design Validation before Fabrication; X-Fab comments on success

"We have found that SEMulator3D builds 3-D models faster and with greater accuracy than conventional TCAD process simulations, and these models are obviously much more accurate than manual drawings of 3-D structures or 2D cross-sections. The benefits of visualizing accurate 3-D virtual MEMS prototypes include increased probability of achieving first-time success by minimizing analysis errors, increased design efficiency by identifying process errors early, avoiding undesired effects that would have reduced yield, and more efficient communication between design engineers and outside groups."
-- X-Fab Semiconductor Foundries

Publish 3-D MEMS and Semiconductor device models in Acrobat 3-D pdf files

Process Documentation made easy.

Are you tired of manually drawing process flow cross-sections? Tired of drawing sketches of devices for presentations?

There is a better way to transfer process knowledge, communicate about engineering decisions and create valuable presentations. With SEMulator3D you can automatically create cross-sections in full 3D, automatically create process flow presentations and even create process animations and interactive 3D content for PDF documents.

With SEMulator3D you can export your 3D Device and Process models right into Adobe Acrobat 9 Pro Extended.
Click on the image to download a sample Adobe Reader PDF file with a 3D model of a Digital Mirror Device.(File size = 1.5 MB)

SEMulator3D 2008.100: New Selective Wet Etch and MEMS Lift-Off capabilities

SEMulator3D 2008.100 enables more realistic wet etch emulation and MEMS lift-off.

Wet isotropic etch steps are commonly used in both Semiconductor and MEMS process flows. Wet etches are usually etch both laterally and vertically (ie, are isotropic) and etch different materials at different rates. The new "Selective Conformal Etch" capability realistically emulates wet etches by allowing the user to control both the vertical/lateral etch rates and individual material etch rates.

In MEMS technology, release etch steps commonly cause pieces of material to become detached from the wafer. These small pieces are usually flushed away by the etchant. A new "Lift-Off" function in SEMulator3D 2008.100 identifies separated pieces of material and removes them from the wafer.

Visit the SEMulator3D Download Center or contact your Coventor support representative for details about how to upgrade to SEMulator3D 2008.100.