ScanChainECO Datasheet

DS-DFT-01

ScanChainECO utilizes an innovative algorithm to assist design teams in efficiently accomplishing scan chain fixing tasks and minimizing test coverage loss resulting from functional ECO.  Based on user’s design changes, ScanChainECO modifies the original scan chain netlist to 

create a revised netlist that accommodates the updated logic function.

Solution Benefits

•  Offering short turnaround time for designs of all sizes and 

complexities

•  Ease of use and optimized patch for optimal scan chain results

• A Plug-and-Play tool easily integrated with 3rd-party design flow

Traditionally, DFT engineers must mitigate the scan chain loopholes created during a functional ECO task.  Since scan chains 

and test patterns are typically generated 

by ATPG tools, DFT engineers often lack 

an effective way to make necessary 

modifications based on the changes 

reported in the ECO patch.  They either 

recreate both the scan chains and test 

patterns, which leads to a complete waste 

of previous design efforts, or choose to 

ignore the newly added flip-flops, 

resulting in reduced test coverage.

                        Figure 1: Scan chain fixing needs across design phases

The figure on the left illustrates the ScanChainECO tool 

flow, where:

1. The input for scan chain FFs can either be the ECO 

report generated by a 3rd-party ECO tool or a list created manually by the user for a specific ECO case.

2. The ECO scan chain represents the result of the 

modifications made to the original scan chain netlist.

SDFF Selection and Conversion

Converts regular DFFs into appropriate SDFFs 

that need to be inserted into the scan chain.

ScanChain Stitching, Removal and 

Balancing

Stitches SDFFs into the original scan chain 

while disconnecting unnecessary SDFFs.  

Customizes the chain length based on user’s 

DFT constraints to meet the requirements of

the test plan, enabling increased test coverage 

without compromising testing costs.

Support for Advanced Design Requirements

Ensures compliance with design rules while 

implementing scan chain revisions.  Identifies 

multi-clock domains, multi-power domains, and 

hold time violations and applies necessary 

adjustments, such as isolation/level shifter cells 

or lockup latches.

Physical-Aware ECO Algorithm

Utilizes the physical information provided by the

     user to enhance the timing of the scan chain.

     Multiple Types of Post-Mask ECO Resource

     Resource options for a post-mask ECO task include 

     spare cells, gate arrays, and filler cells.  When 

     combined with physical information, optimizes the 

     delay of scan chains by considering cell function 

     and estimated wire delay.

     Versatile Design Flow Support

     Supports various ECO flows for introducing changes 

     of FFs, including 3rd-party ECO flow, manual ECO 

     flow, and EasylogicECO flow. It utilizes standard 

     formats for input/output data, enabling seamless 

     integration with mainstream design flow.

     Command Line Script Operations

     Script-based operation is simple, easy to learn and 

     debug.  It only requires modifying specific script fields 

     when migrating to other projects.