CAST Working Groups

CAST is supervised by a Steering Committee that determines policies and priorities and analyzes new initiatives and activities. CAST addresses ongoing pre-standard technical discussions and other topics through Working Groups. This page summarizes the activities and scope of the CAST Working Groups (WGs).


Standard Test Data Format (STDF) New Frontiers WG

The STDF New Frontiers WG is currently working on creating a schema for the existing STDF standard to enable efficient access to data for new applications (e.g., adaptive test). The base schema definition will be used to add additional capabilities required to support new applications. The new format will allow backward compatibility to existing STDF in terms of information content. Participants include key players in ATE companies, instrument companies, end use fabless and IDM companies, and software tool providers.

Interested parties should contact group's chairman Ajay Khoche ( for any questions or additional information.

SEMI G91 Standard developed by the STDF WG.


Test Cell Communication Standard (TCCS) WG

Semiconductor test operations involving ATE today are experiencing increasing use of data for real-time data analysis and real-time ATE input and control to improve test yield, throughput, efficiency, and product quality.  At the same time, test equipment and test operations around the world utilize a diverse range of data formats, specifications, and interface requirements that create significant customer service and application engineering costs for ATE vendors, OSAT companies, IDM test operations, software providers, and handler equipment.

To reduce the cost, time and complexity of integrating ATE equipment into data-intensive test operations, the Work Group is exploring common ATE hardware and software communications interface standards. The vision of the WG is that a common ATE data communications interface can be developed, documented, promulgated, and promoted as a SEMI Standard, subject to industry-wide review and revision. 


Standard Test Interface Language (STIL) WG 

*Activity of SEMI-CAST STIL WG (SCSWG) has completed by 2014/3/31.

The STIL WG is currently based in Japan and involves 12 companies, chaired by representatives from Toshiba and Advantest.  The goal of the WG is to:

Promote STIL test program:

  • Test information uses STIL on all the development processes
  • Tester input language is STIL, output language is STDF
  • To share the test program (pattern, main (tester constraint) program)

Establish common interpretation and usage way of STIL:

  • To eliminate STIL dialects, summarize the issue points and its resolutions into STIL Usage Guides
  • Tools and devices support STIL by complying STIL Usage Guides

The WG has produced a STIL Usage Guide to facilitate STIL usage and support the industry.  For additional information and access to the STIL Usage Guide, please visit

Docking and Mounting WG

The Docking and Mounting WG has produced Generic Terminology Guideline document to assist equipment operators, specifiers, service personnel, and other industry stakeholders involved with test cell equipment features, specifications and operations.  The Docking and Mounting Terminology Guide defines the generic terminology for all components that are typically found in a standard test cell set-up in final package test including perspectives, orientations and directions.

The Terminology Guide was developed by a diverse group of suppliers, users and other industry professionals to standardize common terminology among manufacturers of test cell equipment and their customers--aiding sales, application and service operations.  The well-illustrated document covers test head/manipulator components and motions, test head swing positions, Device Under Test (DUT) positions, including swing and tumble motion definitions.  For a copy of the Guide, click here.