INEMI PROJECT RECOMMENDS METHODOLOGY FOR QUALIFYING NEW PACKAGING TECHNOLOGIES

Several recent developments in the electronics manufacturing supply chain are posing challenges for companies needing to qualify new packaging technologies and materials. These include:

• Development of integrated circuit (IC) packaging is shifting away from device manufacturers to OSATs, distancing the development of new package technology and materials further from the end user, whose PCB and system assembly processes and product application conditions may not be fully known to the OSAT
• With this shift it is vital that qualification reports be more comprehensive in terms of the testing that is performed on new package technologies and materials to allow end users to more accurately assess the potential reliability of the new technology in their applications
• Industry standards for device qualification are not generated/updated in a timely fashion to include new application spaces and the use conditions for the new application spaces, nor are the necessary test methods generated in a timely fashion to address new failure modes for new and existing application spaces
• There is no comprehensive industry document that outlines procedures for the development and assessment of new package technologies and materials nor for the qualification of devices in which they are used

INEMI's New Packaging Technology Qualification Methodology project, completed earlier this year, identified and developed a draft methodology for qualifying new packaging technologies for a broad range of applications. Their recommendations for an improved methodology addresses the need for a stronger understanding of anticipated use conditions (including manufacturing and shipping) and the tools and best practices that should be leveraged to ensure consistency across the industry, enabling faster assessment of new materials and, ultimately, faster and more successful qualification of new packaging technologies.

Current industry standards

The project team identified gaps in current test methods and qualification standards for advanced packaging technologies. Several industry standards commonly used to qualify packages for IC devices (qualification plans, tests methods and pass/fail requirements) were studied in the initial phase of the project. However, none of these standards addresses the entire process for qualifying a new package technology/material, nor do any of them recommend which industry best practices should be used (e.g., how to identify the best material set, implement failure mode and effects analysis (FMEA), and assess all possible customer assembly and field conditions).

Identifying industry needs

In the course of the project, two industry-wide surveys developed by the team polled organizations from the electronics manufacturing supply chain to gain a better understanding of the needs of the IC packaging industry with regards to developing, assessing, and eventually qualifying new package technology and materials. Respondents were drawn from across the industry, including IC package assembly houses, OEMs and EMSes, and others, such as wafer fab foundries, fabless design houses, package material manufacturers, national institutions and universities (see Figure 1).

Results from the two surveys highlighted a gap between supplier and customer knowledge regarding the use of new technologies and materials, as well as differences between field use conditions and the qualification stress conditions required to support the use conditions. This discrepancy emphasizes the need for greater sharing of information among companies, from end use conditions to qualification results. In particular, the awareness of what failure mechanisms could occur with new package technology and how best to test for those mechanisms can be improved and would greatly benefit from the generation of an industry guideline of best practices. A large percentage of the respondents had knowledge of the six qualification methods, practices and tools that our surveys mentioned, but the level of usage varied between users and suppliers. This difference in understanding and use confirms again the need for an industry guideline of best practices.

Survey responses also indicated that application use temperatures are changing, with some applications going higher than the current 150°C upper limits, and a few going below the -65°C lower limits of reliability stress tests that are supposed to accelerate use conditions. Similarly, the fact that some survey respondents, who are striving for zero defects, have extended their test durations indicates an awareness that improvements are needed in industry test methods and to the requirements within qualification standards. For example, analysis of the survey recommended that industry standards bodies reassess the temperatures that define current application spaces for the following:

• Maximum use temperatures above 150°C for applications such as down hole drilling (e.g., oil wells), automotive underhood (e.g., gearbox, tire control)
• Junction temperatures above 150°C for some RF power amplifiers
• Minimum use temperatures below -65°C for deep space, Antarctica, and computers at cryogenic temperatures (e.g., quantum computers)

Lastly, device users pointed out a large discrepancy between the type and amount of information needed from a qualification report to be able to assess whether a qualified device could be reliably used in their product versus the information that was typically provided by device suppliers in their qualification reports. This last finding highlights the need for better standardized communication across all members of the supply chain from end users back to package development teams. To address this need, the team recommends that industry organizations may need to establish working groups to identify the concerns of suppliers and users and provide viable solutions to enhance communication.

Project conclusion

The project team developed a draft methodology that identifies methods and practices that can characterize new package technologies and material performance under various stress conditions. Comparison of this performance with particular use application life stress conditions can indicate whether a specific package technology can be certified or qualified to meet a particular application. The qualification methodology proposed by the project team:

• Creates a repository for all the best practices used today
• Provides background about why and when to use a specific stress or test
• Outlines what to consider when developing a qualification plan and many aspects required for evaluating and assessing new package technology

Key areas of the methodology are highlighted in Table 2. This methodology will be shared with the JEDEC standards body with the recommendation that JEDEC complete the methodology and publish it as a companion document to JEP001, “Foundry Process Qualification Guidelines.” This would provide the industry with one comprehensive, forward-looking guide that could assist in faster and more successful evaluation and qualifications of new packaging technologies. The project team welcomes other approaches, recommendations, contributions, and/or leadership from other industry organizations to help develop this methodology further.

Table 2. Key Areas Addressed in INEMI Methodology

Project report published

The New Packaging Technology Qualification Methodology project recently published a report that details the project team's recommendations to address gaps identified in current test methods and qualification standards for advanced packaging technologies. Their recommendations for improving package and materials qualification methodologies emphasize the need for a stronger understanding of anticipated use conditions. The report recommends tools and best practices that should be leveraged to ensure consistency across the industry, enable faster assessment of new materials and, ultimately, faster and more successful qualification of new packaging technologies.

INEMI New Package/Material Qualification Methodology, Project Summary Report (v 1.0, June 23, 2020)