Multi Chip Project editor

Mask costs have been soaring over the past years, now reaching millions of dollars for the most advanced processes. This makes the use of Multi-Project Wafers (MPWs) or shuttles more attractive to end users, especially in the case of low production chips, prototypes for system integration and testing, and hard IP validation.

MPWs induce specific challenges to the mask data preparation team:

Customer projects must be synchronized. Whether chips are coming from external customers or internal teams, mask data preparation engineers have to deal with last minute project changes, and make sure that every layout database is free of manufacturability issues,
An additional chip assembly step is necessary to maximize the number of chips placed into the reticle while minimizing the number of wafers needed to deliver all the chips,
Managing huge and heterogeneous layout databases is critical, as assembling projects from different providers may generate database consistency problems that need to be detected before tape-out.

Often these operations are handled manually, making it a lengthy and error prone process, at a stage where errors can be very costly.

GTmuch - Multi Chip Project Editor

GTmuch is a powerful and fully automated solution for MPW or shuttle management, which enables mask designers to avoid costly errors and cut time to manufacturing.

Mask data preparation engineers can easily assemble heterogeneous chips onto a single reticle, making sure that the input databases from the different project teams are consistent and manufacturable. GTmuch dedicated placement tool optimizes silicon usage, while minimizing the number of cut sets necessary to produce all chips. GTmuch creates fully verified manufacturable chip assemblies and associated user documentation in a matter of hours.

GTmuch, along with its option GTmask and GTframe provides the first complete and fully integrated Mask Data Preparation flow commercially available.

Key benefits

GTmuch has been developed to automate the entire MPW management flow:

Avoid costly errors, with full flow automation and checks performed at every step of the flow,
Increase engineering productivity. A complex chip assembly is performed in a matter of hours, and repetitive tasks are done in minutes, such as database consistency checking, and end-user documentation generation,
Maximize the number of produced chips, with a sawing-line aware placement tool, that improves density and die size,
Increase factory yield with metal filling capability at the reticle level.

Main features

MPW-Dedicated Placement

GTmuch placement engine has been developed to specifically tackle the problem of multi-chip assembly. It computes the best chip placement inside the reticle, combining multiple optimization criteria:

Silicon area minimization in order to place more chips inside the reticle,
Cut sets minimization in order to minimize the number of wafers necessary to produce all chips,
User-specific grouping in order to keep chips sharing the same property together (end-customer, bonding type,...)

GTmuch placement tool provides the ability to quickly create arrays of chips, align chips, manually tweak the assembly, while still making sure that the resulting project meets all design rules thanks to a high-performance assembly rule checker.

Mask data preparation teams can start working on the floorplanning before all final projects are in, since GTmuch can place final layout databases, as well as “virtual chips” that can be replaced with the real thing in a matter of seconds once they become available.

GTmuch placement tool is able to place hundreds of chips in minutes.

Metal fill

With today's advanced processes, it is necessary to enforce a good planarization of the wafer in order to keep a high manufacturing yield. GTmuch automates the insertion of dummy tiles in empty areas of the reticle, between and around the chips. GTmuch metal filling engine inserts full layers or user-defined dummies, according to any kind of user-defined rules. To increase manufacturability sawing lines can be kept clear of metal filling.

GTmuch metal filling engine generates in minutes a very compact “dummy tile database” whose size is in the order of KBs.

Checks and Validation

GTmuch avoid costly assembly errors by running checks at every stage of the flow.

Any chip entering the assembly is checked for correctness. GTmuch file integrity checker reports any error or warning in the input GDSII or OASIS database, such as missing cells, re-entrant polygons, etc..) and is able to handle a 1GB input file in less than a minute.

Any manual modification to the automatic placement is checked by GTmuch assembly rule checker that makes sure that no design rule is violated prior to the generation of the output assembly database.

Whether customers chose to create a single output database, in GDSII or OASIS format, or a composite output database with a jobdeck file and associated GDSII or OASIS databases, GTmuch provides a powerful layout database merging engine, which makes sure that no conflict arises by combining multiple heterogeneous databases, such as name conflicts, different database units. The check is performed at a rate of 1 minute per GB and ensure that the final output database is fully manufacturable.

Documentation Generation

Mask data preparation teams assembling complex MPW projects have to generate a detailed documentation that is targeted for the end users, as well as for the manufacturing line. GTmuch automates this tedious task. A user-customizable documentation is generated in a matter of seconds that only contains information relevant to the recipient and provides information on chips, sawing line, silicon usage, etc...

The documentation is available in PDF and Postcript.

Link to Administrative Databases

GTmuch provides a direct access to the MPW database, that can be used to drive other systems such as the assembly line equipment, or the customer billing system. Access is available through an XML output, that can be viewed on any web browser, or entered in any SQL-based enterprise database.

User Interface

GTmuch offers an intuitive Graphical User Interface (GUI), which enables the complete control of the MPW assembly flow. The GUI is fully customizable, and supports “cut & paste” between different projects to increase reuse.

GTmuch is also available through the command line making it fully scriptable and enabling automatic processing and easy inclusion in an existing flow.

Frame Generation (optional)

GTmuch is fully integrated with GTframe, a powerful Mask Data Preparation tool, which automates the insertion of manufacturing items into reticles, between chips or inside scribe lines according to reusable process rules.

Mask Generation (optional)

GTmuch offers an option, GTmask, which simplifies the creation of the most advanced mask sets with intuitive support for Multi-Layer Reticles (MLRs) , optimized 1X mask flow, and Wafer Map optimization.

Performance 

GTmuch is able to place hundreds of chips in minutes.
GTmuch is used in production since 2000.

Technology

Based on a graphical editor, GTmuch comes with a comprehensive suite of layout finishing tools:

A GDSII/OASIS/MEBES file integrity checker which warrants each contribution of the project
A GDSII/OASIS database merging program
A dummy tiles filling program which operates only on empty areas between chips
A virtual chip generator to anticipate floorplaning construction
An optional module for frame generation
An optional module for mask and wafer map generation
An optional GDSII/OASIS viewer

Supported platforms

SUN Sparc Stations, 32 and 64 bits, Solaris 2.5 and + HP HPUX 11.x x86 PC Linux RedHat 3 and + x86-64 PC Linux RedHat 3 and + ItaniumII Linux RedHat 3 and +