Reliability Data

Overview and Philosophy

Reliability is the ability of a product to perform under stated conditions for a specified period of time. Generally, reliability levels are expressed as the probability that a part will fail to function after a specified time interval. The same part will have different probabilities of failure under different use conditions.
In the electronics industry, this failure rate over time exhibits characteristics that, when summed, are commonly referred to as the “Bathtub Curve”. This curve is typically divided into the three regions depicted below (Early Failure Rate, Intrinsic Failure Rate, Wear Out Failure Rate).

The specific shape and position of the bathtub curve is dependent on the product design, material, processing and defect density for both die and package. When considering the overall reliability of the product, the intended application(s) and the board/system level manufacturing processes will contribute to the observed reliability. As the knowledge and understanding of all these factors grows, designs and processes can be implemented and improved to ensure a robust and reliable product.

3D PLUS screening module performed on 100% of our Engineering and Space products ought to eliminate early failures, when the Lot Acceptance Test performed on a sampling given by standard is in place to ensure reliable products after time without achieving the wear out zone.

As products can operate in a system for more than twenty years without failing, any test designed to accurately evaluate reliability must utilize accelerated use conditions. This acceleration is achieved through the use of extreme environmental (temperature, humidity, pressure) and operating (voltages, currents) conditions that serve to shorten the overall test times to more manageable levels. Even under accelerated conditions, these tests may take several months to complete.

3D PLUS supplies high reliable products to its customers using its high reliable stacking technology proven since 1995 and with more than 100 000 products in Space.

Highly Accelerated Stress Test (HAST)

The purpose of this test is to evaluate a plastic packaged component’s ability to withstand harsh environmental conditions with extreme temperature and humidity levels. The parts are stressed to high temperature (110°C) and relative humidity (85%RH) conditions for a define period (264hours) in a biased state to achieve maximum acceleration (JESD22-A110).

Reliability Qualification Methodology

Methodology to ensure that the requirements for Product Assurance aspects comply with the contractual requirements specified in agreement with the client.

The main objectives are:

• Ensuring that the products supplied by 3D PLUS in the contractual framework of a project achieves the objective defined mission and that these products are safe, available and reliable,
• Participate in the project that offers the best cost effectiveness by implementing appropriate product assurance methods,
• Contribute to project risk management by ensuring, as appropriate, identification, evaluation, prevention and control of risks in accordance with the technical constraints of the project including the following two points to take into account very early: 
  • Electrical, electronic, electromechanical (EEE) components
    The objective associated with EEE components is to ensure that the components meet the requirements of mission accomplishment during the entire life cycle of 3D PLUS product.
  • Materials and Processes Mechanical Components
    The objective associated with materials, Mechanical Components and Process is to ensure that the use of these satisfy the realization of the mission requirements.

The 3D PLUS Product Assurance Manager makes sure all the selection, evaluation / qualification has followed ESA ESCC 2566001 Process Capability Approval standard and add on detail specification. The Product Assurance Manager is in charge to prepare and coordinate customer source inspection (precap, CSI, Buy Off) and gather all necessary traceability for the key elements such as:

• EEE components
• Materials
• Mechanical components

Data Retention Bake (DRB)

This test is used to measure a device’s ability to retain a charge for extended periods of time without applying voltage bias. Stressing at high temperatures (125°C) accelerates any discharge causing the memory state to change.

Electrostatic Discharge (ESD)

Device’s sensitivity is mainly driven by components sensitivity. 3D PLUS package does not impact ESD Device sensitivity. Human Body Model (HBM) min. value for 3D PLUS catalog products is 2KV (JS001-2014).

Life Test

This test is performed in order to evaluate a device’s ability to be still functional, programmable, erased, and verified after a long time period, which represents end of product life in the “Bathtub Curve” or about more than 12 years for 1000hours.

Temperature Cycle (TC)

This test is used to measure a product’s sensitivity to thermal stresses due to differences in expansion and contraction characteristics of the die and package materials by repeated alternating temperature dwells between high (+125°C) and low (–55°C) temperature extremes.

Reliability Modeling

Failure rates for 3D PLUS products are typically calculated based on test data with acceleration factors based on the Arrhenius Model for thermal acceleration. The other model, Coffin-Manson (temperature cycling) may be used for specific applications or customer concerns.

Failure Rate

Failure rate is the frequency with which an engineered system or component fails, expressed in failures per unit of time.
In practice, the Mean Time Between Failures (MTBF= 1/λ) is often reported instead of the failure rate.
The Failures In Time (FIT) rate of a device is the number of failures that can be expected in one billion (10⁹) device-hours of operation.
This is valid and useful if the failure rate may be assumed constant – often used for complex units / systems, electronics – and is a general agreement in some reliability standards (Military and Aerospace). It does in this case only relate to the flat region of the bathtub curve, also called the "useful life period".

Reliability Calculation

The reliability behavior of each module is characterized by using the MIL-HDBK-217F + N2 standard based on model for Overall Hybrid Part, the UTE standard C 80-810 dated July, 2000 for Failure Rate Calculation, and by taking into account the following documents:

• Supplier qualification report
• 3D PLUS evaluation / qualification database and 3D PLUS background
• 3D thermal analysis output (see § VIII thermal management)
• Customer specification (module environment, module reliability requirement, …)

Thus the 3D Module reliability assessment can be validated by the customer before the manufacturing.

Reliability Monitoring

Once a year, 3D PLUS Quality is releasing representative quality data of products subjected previously to the stress tests for reliability qualification. These data are gathered from one-year manufacturing testing. This release is completed to ensure that the reliability of 3D PLUS stacking technology continues to meet the assigned goals since its initial qualification in 1995.
These data are accumulated over several years to determine reliability trends in manufacturing, design rules, and assembly processes. Additionally, this data allows customers to predict the expected reliability performance of their overall system (see documents bellow).

Radiation

With more than 125 000 modules in Space as of 2017, and with more than 18 years of Flight Heritage with no Failure reported, 3D PLUS is the largest Hybrid Space Qualified catalog products and custom System-In-Packages (SiPs) manufacturer in Europe. 3D PLUS Radiation Assurance Policy has been initially set-up for its Radiation Tolerant Products, and it covers all the effects induced on the semiconductor devices by the Space radiation environment.

Failure Analysis and Corrective Actions

In order to continuously improve reliability, it is mandatory to understand the root cause of failures and prevent their recurrence. A systematic approach is necessary to ensure that the more prevalent failures are eliminated first. 3D PLUS has a policy to analyze every reliability failure for root cause identification using 8D problem solving methodology. Sources of failures include customer returns (RMA) and internal reliability evaluations. Supported by an outstanding discipline and expertise, 3D PLUS succeeds on eliminating or reducing several failure mechanisms in recent years.

Reliability Targets

Results of the reliability monitoring and qualification programs help 3D PLUS trend to zero defects.

3D PLUS Products Reliability

LAT = Lot Acceptance Test 1000hrs@125°C.
DPA = Destructive Physical Analysis

More Reliability Data on request, please complete contact form.

Documents