What is QML in Defense Manufacturing?

Kevin McCarville, Director Test Operations, VORAGO Technologies
William “Pat” McCord, Quality Technician, VORAGO Technologies

September 25, 2024

What is the Qualified Manufacturers List (QML) and why is it important in defense product manufacturing?

What is the Qualified Manufacturers List (QML)?

QML, which stands for Qualified Manufacturers List, is a designation used in the semiconductor industry, primarily in the context of military, aerospace, and high-reliability applications. QML certification ensures that semiconductor devices and components meet stringent quality, reliability, and performance standards required for these critical applications. The QML is administered by the United States Department of Defense (DoD), specifically by the Defense Logistics Agency (DLA).

The QML aligns with the Department of Defense's industrial base policy, which aims to ensure a resilient and adaptable defense industrial base. This policy focuses on resilient supply chains, workforce development, and economic deterrence to strengthen national security and support international allies.

Importance of QML Certification

QML for semiconductors is a critical certification process that ensures devices are suitable for use in the most demanding environments, providing a level of assurance and reliability necessary for military and aerospace applications. QML qualifies both the company and the processes used to create the product as well as the product itself, so organizations purchasing semiconductors from manufacturers on the QML list can trust that they are buying products that adhere to the highest levels of reliability and quality.

Benefits of QML Certification

• Benefits to Customers: QML builds customer confidence by ensuring consistency in product quality and reliability. Specifically, QML helps customers with risk mitigation by lowering the chance of failure, and reducing warranty and liability costs:

  • Lower Risk of Failure: Using QML-certified components ensures that the risk of failure is significantly reduced due to the stringent testing and qualification processes involved. Semiconductor companies with QML certification provide their customers with the assurance that their products meet the most demanding reliability and durability standards. This is particularly crucial in the defense industry, where high-quality components are essential for military applications.

  • Reduced Warranty and Liability Costs: Since QML-certified components are designed and tested for high reliability, they typically have lower failure rates in the field. This reduces warranty claims, liability risks, and the costs associated with recalls or replacements, which is attractive to customers looking to minimize operational and legal risks.

• Benefits to Manufacturers: Inclusion on the QML benefits manufacturers by allowing them to be included in the consideration set for projects funded by the Defense Logistics Agency (“DLA”) and other government entities. QML certification is significant in the defense sector, enhancing manufacturers' roles in government contracting and ensuring they meet the stringent requirements of national security projects.

The Role of QML in Ensuring Semiconductor Quality

Quality assurance is seen throughout every step of the process for QML vendors, from comprehensive testing protocols, early defect detection and robust failure analysis to specific controls for processes, suppliers and materials, long term reliability testing, full production traceability, and ongoing compliance procedures coupled with regular audits. Advanced manufacturing technology plays a crucial role in ensuring semiconductor quality by enhancing the efficiency, reliability, and affordability of manufacturing processes.

These processes all contribute to a more reliable production environment and ensure quality, uniformity and consistency across production batches. Uniformity reduces the likelihood of variability, which is crucial in semiconductor manufacturing where even small deviations can lead to product failure.

Testing Standards for Semiconductors

Given the increasing complexity of modern semiconductors, rigorous testing is crucial for delivering devices that meet the demanding requirements of today’s industries, particularly in high-reliability sectors such as aerospace and defense. Testing plays a vital role in defect detection, performance verification, compliance with industry standards, and the overall improvement of manufacturing processes.

In the aerospace and defense manufacturing industry, stringent testing standards are essential to ensure the reliability and performance of critical components. Chips are exposed to both mechanical and thermal stressors and then re-tested electronically to ensure compliance with all applicable specifications.

• Testing Provides Performance Verification: Chips often need to meet specific performance criteria, such as clock speeds, power consumption, and thermal limits. Testing verifies that these parameters are within acceptable ranges, ensuring the chip will perform well in its intended application.

• Testing Helps to Ensure Long-Term Reliability: Many semiconductor devices, especially those used in mission-critical applications, must perform reliably over extended periods and in harsh environments. Testing evaluates a chip’s ability to withstand radiation, temperature variations, electrical stress, and environmental factors over time.

Types of QML Certification

The QML program encompasses a number of different types of QML certifications, each tailored to specific categories of semiconductor products. The different types of QML certifications—ranging from Class V (space-grade) to Class B (commercial-grade)—cover a broad spectrum of reliability requirements for semiconductor devices, ensuring they meet the necessary standards for their intended applications. QML Class V is the Space-Grade certification, while QML Class Q is Military-Grade.

QML Class V (Space-Grade) certification is the highest level of qualification for semiconductors, designed specifically for components used in space applications. These products must meet extremely stringent quality, reliability, and radiation tolerance standards, as they will operate in harsh environments with high radiation exposure, extreme temperatures, and long-term reliability requirements.

• QML Class V Standards: Governed by MIL-PRF-38535, Class V certification ensures that the devices can withstand the harsh conditions of space without failure.

• QML Class V Testing Requirements:

  • Extensive radiation testing, including Total Ionizing Dose (TID) and Single Event Effects (SEE).

  • Rigorous environmental testing, including thermal cycling, mechanical shock, vibration, and burn-in testing.

  • Long-term reliability testing to ensure functionality over the mission life of a spacecraft.

• Typical Applications for QML Class V Parts: Satellites, spacecraft, deep space probes, and other space exploration missions where failure is not an option.

QML Class Q (Military-Grade) certification is aimed at semiconductor products used in military applications, ensuring that they meet high-reliability standards necessary for defense systems. While not as rigorous as Class V, Class Q components are still subject to stringent testing and quality control measures to ensure they perform reliably in demanding environments.

• QML Class Q Standards: Also governed by MIL-PRF-38535, Class Q certification has slightly less stringent radiation tolerance requirements than Class V but still demands rigorous testing.

• QML Class Q Testing Requirements:

  • Environmental and electrical stress testing, such as temperature cycling, burn-in, mechanical shock, and vibration.

  • Reliability testing to ensure operation under extreme conditions found in military applications.

• Typical Applications for QML Class Q Parts: Military avionics, radar systems, missile guidance, communication systems, and other defense-related applications where high reliability is essential.

Radiation Hardening for QML

For products intended for space and other radiation-prone environments, manufacturers must conduct radiation hardness testing to ensure that components can withstand exposure to ionizing radiation. The process of ensuring radiation hardening involves a combination of specialized design techniques and processes rigorous radiation testing, and strict process control.

• Total Ionizing Dose (TID) Testing

  • TID testing evaluates the long-term cumulative effects of ionizing radiation on semiconductor devices. MIL-STD-883, Method 1019 outlines the procedures for TID testing to ensure compliance with military specifications. Devices are subjected to radiation doses of varying magnitudes, depending on the application, with aerospace components typically requiring testing to levels of 100 krad (Si) or higher. To achieve QML RHA certification, devices must demonstrate the ability to perform reliably without significant degradation over the entire expected radiation dose lifetime.

• Single-Event Effect (SEE) Testing

  • SEE testing focuses on identifying the susceptibility of devices to single-particle strikes, which can cause transient or permanent disruptions. JEDEC JESD89 outlines the SEE testing procedures for ensuring that semiconductor devices are resistant to SEE, including methods to test for different types of SEE and their corresponding mitigation techniques. The device must demonstrate resilience to SEEs, or include internal error correction mechanisms, to pass the QML RHA certification criteria. For example, SELs must not lead to catastrophic failure, and SEUs must be corrected by design or fail-safe mechanisms.

QML certified companies can gain an additional level of certification called Radiation Hardness Assurance (RHA), which is separate from the basic QML certification. Both QML and RHA are not simply about product design – RHA is also certifying the processes used to create radiation hardness. To achieve and retain RHA certification, semiconductor manufacturers must follow well-defined industry and military standards, conduct comprehensive testing for total ionizing dose (TID) and single-event effects (SEE), and maintain strict process monitoring and auditing.

Companies can achieve these standards and self-certify without being part of the QML, but certifying as RHA within the QML program assures that the DLA is watching over the process, and even approving the testing plan in advance.

The Impact of QML Certification on Semiconductor Companies

• Market Implications

  • Only a short list of semiconductor companies achieves QML certification, putting them in an elite group that is known for high quality and reliability.

  • The program benefits from the authority of the DLA as a compliance watchdog. While the DLA is not the exclusive author of the MIL standards, they serve as an enforcer via the QML program, providing checks and balances and lending the weight of the government to the qualification process.

  • Achieving QML certification sets companies apart in the market by confirming their commitment to rigorous quality standards and reliability. In addition to enabling direct access to bid on government contracts, QML vendors gain credibility and brand trust, and often become preferred suppliers for government agencies, defense contractors, and large corporations in aerospace, medical, and automotive sectors.

  • Additionally, QML certification is recognized internationally, enabling semiconductor companies to compete in global markets by providing products that meet the most rigorous international standards.

Overcoming Challenges in QML Certification

Obtaining QML certification is a significant milestone for semiconductor manufacturers. However, achieving and maintaining this certification involves several challenges, particularly related to stringent requirements, operational costs and complexity, time investment, and ongoing compliance to maintain standards set by government agencies and industry bodies.

• Stringent Requirements: QML certification requires compliance with military and industry standards, such as MIL-PRF-38535 (for microcircuits) or MIL-PRF-19500 (for discrete semiconductors). These standards mandate extensive documentation, specific manufacturing practices, and rigorous testing protocols. Manufacturers must maintain comprehensive records of their processes, testing results, and quality control measures. This documentation must be accurate, traceable, and regularly audited by external bodies.

• Operational Costs and Complexity: Achieving these high standards often involves significant costs to purchase specialized testing equipment or partner with a testing company that is equipped to conduct burn-in, thermal cycling, vibration tests, and more. Meeting QML requirements may also increase manufacturing costs to adhere to strict process controls.

• Time Investment: QML certification is a lengthy process that can take several months to years, depending on the complexity of the products being certified and the readiness of the manufacturing processes. In addition to time-consuming testing processes, QML also requires that a manufacturer’s entire supply chain, including the materials and components used, adheres to specific quality and traceability standards, adding time and operational complexity.

• Ongoing Compliance: QML certification is not a one-time achievement; it requires ongoing maintenance. Manufacturers must regularly submit to audits and performance reviews to ensure continuous compliance. This can involve retesting products, revalidating processes, and updating documentation, all of which are resource intensive. Constant, consistent monitoring and process controls are critical, as well as carefully managing any changes to processes or materials. Any changes to the manufacturing process, materials, or suppliers can require requalification, which involves additional testing and documentation.

Contact VORAGO for QML Certified Products

VORAGO Technologies was granted certification by Defense Logistics Agency for QML, MIL-PRF-38535 manufacturer, class level Q & V Radiation Hardness effective September 2024. The certification letter number is: VQC-24-038982 and the lab suitability letter number is: VQC-24-038983. With this achievement, VORAGO joins a short list of just 12 companies on the DLA’s list of radiation hardened Q & V Level Certified QML/38535 manufacturers and is the only startup among this prestigious group.

Interested in QML certified products from VORAGO? Contact Us or Get a Quote