( DAC 03 Item 41 ) ----------------------------------------------- [ 01/20/04 ]
Subject: Silicon Metrics, Prolific, Z Circuit, Zenasis, UbiTech
A LITTLE SABOTAGE: Magma acquired Silicon Metrics. Circuit Semantics was
MIA and presumed dead this year. Synopsys buying Numeritech has temporarily
screwed up Cadence, who relied on their tools for phase shifting and optical
proximity correction. (Cadence is working on another partnership, but won't
talk about it yet.)
I have used Magma/Silicon Metric's SiliconSmart CR, their library
characterization tool. It's a much, much better tool than the Avanti
Master Tool Box we used before. The thing I like the best about
SiliconSmart CR is that it is very easy to port the characterization
setup and configurations across different corners, or even different
processes. The biggest problem we have had is Silicon Metrics'
inability to provide regular bug patches. As a result, we tend to rely
on ourselves to fix the bugs, since we don't have the luxury to wait
till the next major release.
- Jian Ding of Guidant Corporation
Our eval compared Silicon Metrics SiliconSmart to our internal PERL-
based characterization method. We did take a cursory look at Circuit
Semantics a while back, but this was not a head-to-head comparison.
The SiliconSmart software is extremely configurable, almost to a fault.
We're running both standard cell and IO characterizations, with mixed
voltages on inputs and outputs.
The support from a small company has been exceptional, and they have
really worked hard to make our adoption a success. I am hoping none
of this changes now that Silicon Metrics has been acquired by Magma!
The product team is changing the capabilities of the SiliconSmart CR
tool with respect to bidirectional ports, and our technical lead has
been working with us to weather this transition.
Overall, it's a solid product from this customer's standpoint.
- [ An Anon Engineer ]
My company PolarFab is a state-side pure-play foundry. First a little
background about our usage of Magma/Silicon Metrics' SiliconSmart CR
(I'll refer to the tool as CellRater, which was its old name). We have
relatively small libraries -- 110 cells per library or less -- and we
have three main processes we use SiliconSmart CellRater on, 0.8, 0.5
and 0.35um. I drive SiliconSmart CellRater exclusively from the GUI
and haven't put together any batch jobs yet. Also, we use Spectre for
our SPICE simulator.
The CellRater/SiliconSmart CR Bad:
1) CellRater is relatively slow. Running on a 4-processor 750 MHz
Sparc machine, it takes 2-3 days to characterize a 100 cell library
for one corner. To do the fast, slow and nominal corners for a 100
cell library takes a little over a week.
2) The license manager seems to get confused when there's more than a
minimal amount of licenses activity. To deal with this, I may have
to terminate the session, exit the tool and then get back in. This
isn't too bad, more of nuisance.
The CellRater/SiliconSmart CR Good:
1) SiliconSmart does what it is supposed to do. This allows us to
create timing views for our standard cell libraries and develop
SP&R flows for our customers' use.
2) The "verify models" feature is great; every EDA operation needs a
verification step.
3) I'd have to say the customer support has been excellent.
We are waiting for the next release of CellRater which will support the
5.0 version of Spectre (due out end of January '04.) This version of
Spectre runs on Linux whereas previous versions did not. Spectre 5.0
also added a bunch of features that should speed up CellRater's
characterization. So, I am hoping for a 4X to 10X speed up by moving
to this new version of CellRater, which supports Spectre 5.0, and
moving over onto 3 GHz Linux boxes.
- Kurt Kimber of PolarFab
Library Generation and Characterization
Silicon Metrics sells software to characterize libraries. They told me
their primary competition is still internal tools. They support the new
Synopsys SPDM model with signal integrity information and also new
Cadence constructs that provide improved driver models for victim nets.
Until recently there was no standard way to express glitch sensitivity
and glitch information.
Library Technology Inc. sell library characterization tools, but also
has a tool to optimize transistor sizing for delay, power, clock skew,
etc. This sounds like an "analog synthesis" tool being used for digital
libraries.
Prolific sells software that generates the layouts for libraries. They
now have both generators (slow to set up, fast to generate, fair density)
and synthesis (transistor place & route and compaction) (fast to set up,
slow to run, high density). They also sell Protiming, which sizes cells
to optimize timing. It ties to Primetime and they claim they can get
1%-2% improvement using existing cells (what does that say about timing
optimization?) and they've seen 6.5% to 15% timing improvement by
creating new cells at custom drive strengths. They also claim that Design
Compiler uses maybe 5 drive strengths of any given cell no matter how
many different drive strengths are in your library.
Zenasis sells a tool that does transistor level optimization of your
design. The input is a Verilog netlist of your design, LEF/DEF, a
Synopsys library and SPICE description of your cell library. The tool
creates new standard cells that combine cells in the critical paths.
The output is SPICE description of these new cells, which you can create
using Cadabra. They claim a 10%-17% increase in speed using their
technology and say Agilent is a customer. They will also sell services
to create the new cells.
Z Circuit Automation sells a unique tool that compares libraries or cells
within libraries. This sounds difficult to sell but I've worked with at
least 20 libraries in my career and every single one of them has had
bugs. The tool works from a .lib and can compare different revs of the
same library as well as point out the best load/slew ranges for a cell
or a library.
Legend Design Automation sells a tool to characterize memories. They
emphasized the need to characterize a memory for your specific system,
and said they do power characterization as well.
- John Weiland of Intrinsix
Library Technologies
Library Technologies provides a cell characterization tool that supports
standard cells and I/O's at no extra cost. The tool supports the latest
Liberty file formats for timing, power, and noise. For timing, both table
lookup and scalable polynomial delay models (SPDM) are supported. It also
supports state dependent timing, power, and leakage power. The tool does
not do a functional extraction of the cell and thus requires a small
descriptor file for each function. From this functional description, the
tool automatically creates an exhaustive Spice simulation file and
Verilog test bench. Many user control options are provided for things
such as setup and hold time measurement method, noise model generation,
and others. Both Verilog and VHDL models are supported.
- [ An Anon Engineer ]
We used Z Circuit's services for library re-characterization to a
different operating point, to basically reduce some of the over
margining that normally happens during design. Our experience was very
smooth and pleasant. No surprises. They provided us with detailed
comparison reports for each of the timing arcs, for each of the cells
between the two operating points, in a consolidated form to
1. Validate the correctness of the re-characterization, i.e. make
sure that everything that's unexpected or outside of expected
range is explained for completely.
2. Give us a good feel as to what we can expect in terms of the
performance of the library
The Z Circuit library analyzer in general is very versatile and powerful
and can be used to compare libraries to understand their impact on a
given design. Edmond and Fred (the two key people at Z-circuit that I
had the opportunity to work with) are very knowledgeable, and we used
them as sounding boards for some of the issues we had to deal with
during our design. They were very helpful and provided valuable feedback.
- [ An Anon Engineer ]
I think I saw the Z Circuit Library Analyzer demo here. We haven't used
Library Analyzer in any real way. It looks interesting. I don't know
of anything else that does what it does though there are likely some out
there. The bottom line is that no one has found it interesting enough to
take project time to look at it. I suppose that says something...
The net is that I think the tool would be useful. I'd like to look at
it. And, I can't really tell you much more than that.
I've done some work in the past around looking at gobs of data (rspf
comparison plots). From what I saw from Z-circuit, they present the
data in a meaningful way.
There were two uses that we considered for Library Analyzer. First,
comparing library versions to each other. You know, you're coming up
to tape-out and your ASIC vendor says you need to upgrade your library.
You ask what's changed and they can't really tell you. The second use
was more in line with how Z Circuit is marketing their tool: analyzing
libs to look for strengths or weaknesses.
- [ An Anon Engineer ]
I usually do not look at backend tools but the coolest new tool I saw was
from Z Circuit Automation which had a tool to compare two versions of a
vendor library. I am not sure which is worse that this was the neatest
new tool or the fact that we really wish we had a tool to do this.
- Steven Jorgensen of Hewlett-Packard
The company that struck me as the interesting new vendor is Stone Pillar
Technologies and their Silicon Insight Software. They provide linkage
from the fab process, through the transistor level design optimization
business process flow, to the IC design environment. Their data
structures spans process, device, modeling and test structures.
- Peter Hopper of National Semiconductor
Mentor Calibre does optical proximity correction and phase shifting.
UbiTech sells tools to add metal fill for Chemical-Mechanical Polishing
(CMP), which requires that every area of the chip have roughly the same
percentage of metal coverage. They do the setup for xCalibre for easy
extraction setup. Their tool will avoid critical nets if they are
identified.
- John Weiland of Intrinsix
I tried the UbiTech product. It has some benefit in reducing loading
on critical nets, but not enough to justify the price for our
applications.
- Louis Morales of Innotech Systems
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