About the Project
INLINETEST is a European funded project that targets the design, realization, deployment and test of two novel in-line inspection systems for micro/nano-electronic components.
For the first time, the fast, contactless and non-destructive full-field thermometric methods of Pulse-Infrared Thermography (PIRT) and Thermoreflectance (TR) are exploited to enable 100% in-line production monitoring. This will be done by adapting and upgrading existing lab prototypes for both methods to the challenges of real-life in-line testing, enhanced by hard- and software innovations. For validation under real-life conditions, both failure analytical method’s hard- and software will be customized and integrated into two production lines and demonstrated on two encapsulated power multi-chip module (MCM) components and one in-line production tool at the project partners. Three global players in micro/nano-electronics in Europe accompany this endeavor on the board of industrial advisors.
Thermography-Based Quality Assessment
Contactless, non-destructive in-line testing has been the ultimate goal for quality assessors and process managers for decades. Thermography holds the key to finally open that door and to revolutionize production line quality control. Hidden flaws like voids, cracks, delaminations and tilts burried under mold compound are potential factors for early failures and decreased quality output and are not detectable just by visual inspection.
Thermography can be used to analyze a component of sub-component with a surface of nearly any kind. Classical infrared thermography allows observation of non-reflecting surfaces while the newer thermoreflectance thermography is capable of monitoring reflecting surfaces such as bare dies, glass or even polished metal. Both techniques, though based on slightly different phenomena, offer the same gain of information about the thermal stack below the surface under observation.
Micro- and nanoelectronic components are one key driver of today’s industrial growth and have been pervading nearly every domain of modern society and life, tendency: increasing. For that reason, it is a multi-billion-dollar business, extending from low profit margin but high volume consumer components to e.g. high value power and RF components. For the latter, component annual growth rates are predicted to exceed 20% (Source: Yole Development) for telecom, avionics and automotive applications, all of which are key segments of the European electronic industry.
In order to be competitive on these markets, components need to have high quality, i.e. be reproducible, robust and reliable under given environmental conditions. These quality issues are to a great deal determined by their production processes: This is where tolerances, flaws and defects are induced which are responsible for early malfunction of failure in field operation. It is reported that the costs for non-quality (e.g. repair, warranty, rejects) can amount to 5-8% of the turnover. The hidden costs (bad press, long time to market, dissatisfied customers, sinking sales figures), however, are estimated to go beyond 20% (Source: Gottschalk, Quality assurance of electronic components).read more
Quality assurance is therefore of paramount importance and is an integral part of industrially implemented Total Quality Management, Zero Defect or Six Sigma strategies, which demand constant quality improvement. The key to highest productivity at highest yield and lowest cost is 100% in-line inspection during production, to gain intimate knowledge about interdependencies between process steps and process parameters. This paves the way to what is called smart production, where ample measured information concerning key parameters at each process step during production is available in real time to allow 100% individual traceability and immediate feedback in the framework of a big data correlation scheme.
True novelty in failure detection
INLINETEST targets the design, realization, deployment and test of two novel in-line inspection systems for micro/nano-electronic components. Thereby, the fast, contactless and non-destructive full-field thermometric methods of Pulse-Infrared Thermography (PIRT) and Thermoreflectance (TR) are exploited for the first time to enable 100% in-line production monitoring. This will be done by adapting and upgrading existing lab prototypes for both methods to the challenges of real-life in-line testing, enhanced by hard- and software innovations. For validation under real-life conditions, both failure analytical method’s hard- and software will be customized and integrated into two production lines and demonstrated on two encapsulated power multi-chip module (MCM) components and one in-line production tool at the project partners. Three global players in micro/nano-electronics in Europe accompany this endeavor on the board of industrial advisors.
Micro/nano-electronic components fail under field and test conditions due to thermal and mechanical overload or over time (fatigue failures), both of which are governed by the structural integrity of the component. This structural integrity, however, is determined during production by e.g. tolerances in material or processing parameters. This can lead to weak points in the component as e.g. voids, material gradients or inhomogeneity, cracks, delamination, dewetting, or geometric tolerances, impairing robustness and reliability:
- High power transients can damage the semiconductor by overheating due to local thermal hot spots or decisively reduce its lifetime due to the set-in of unwanted diffusion processes.
- Weak spots can lead to thermo-mechanical reliability issues like cracking or delamination.
For that reason, the consortium has decided to demonstrate the envisaged in-line inspection system on two power components from relevant European market segments with also silver sintered die attach material in application, designed also for use in harsh environment:
- A GaN RF HEMT HPA power MCM encapsulated component for avionics and telecom applications, using eutectic solder as die attach material and epoxy molding compound (EMC) encapsulant.
- A Si-based power MCM for automotive applications, using sintered silver as die attach material and an EMC encapsulant.
From Lab-Scale to In-Line Process
It is, however, important to note that the employed failure analytical techniques can also be in-line-applied to non-power components as e.g. advanced packages during ramp-up of consumer products.
The principle of the failure analytical methods on which the in-line inspection systems are based are highlighted in Figure 2. After transient energetic excitation, propagating thermal waves probe the heat path in the component which is determined by the material properties, i.e. also the structural integrity. Aberrations or anomalies can thus be made visible by recording the thermal signature of the component as response to that excitation. This thermal signature (surface temperature over time) is recorded either by PIRT or TR. As one can see, the methods are complementary in the sense that PIRT is sensitive for non-reflective surfaces (e.g. encapsulated components) whereas the other, TR, is sensitive to reflective surfaces. So many stages in the production process can be monitored. One major advantage is that the equipment probes exactly those flaws which are responsible for a later failure by the same physical effect of high temperature. So the thermal contrast detected by the two methods is physically very motivated and justified and better suited than time-honoured methods which, if at all in-line capable, monitor derived qualities as acoustic reflection or absorption of radiation. Further, cooling down time (tens of seconds) after processing can ideally be used for thermographic methods as it is not used otherwise.
So, new information on production process quality can be obtained which has so far been inaccessible, allowing countermeasures and control to potential aberrations in the process flow. This new information renders the production smarter and will thus enable higher yield, narrower tolerances, better reliability, less maintenance cost and thus result in a higher productivity, less waste and higher profits. Limitations of today’s in-line testing
For manufacturing of micro and nanoelectronic components in-line-capable failure analytical techniques must feature capability (detect/measure the defect in question), precision (how good the defect can be detected and differentiated from others without fault) and efficiency (measurements per unit time) by preferably non-contact methods.
The absence of insight: why INLINETEST is necessary
Whereas fast automated in-line equipment is available on the market, the bottlenecks are the respective measurement systems and the real-time data processing. Many methods are too slow to keep track of the production. Thermography is used today already for in-line measurements as it is a fast optical method, but only for approximate thermal resistance determination (e.g. LED). Electrical hot probing is an alternative, but not all samples allow to be electrically contacted at relevant production stages due to their complexity or sensitivity. So, whereas this is done and possible for LEDs on different complexity levels, it is much more complex for RF-circuits, and electrical response signals do not reveal a spatially resolved map of structural deviations from the standard. But a temperature contrast detected on reflective surfaces could. X-raying of samples, often a method of choice, is not sensitive to most surface or small scale defects, especially for low-Z elements (e.g. encapsulants, etc.)
The result is, that often indirect methods are applied, i.e. offline analysis by random sampling tests for process control followed by statistical schemes like six sigma to minimize the risk of failures in the field. Therefore, specifications of the components are chosen that typically reduce the production yield significantly which is of course not desirable.
Testing costs is another limitation which translates into test time and equipment cost. However, for newly designed, advanced high quality products, as targeted here, testing in production is required, and to widen the scope incorporating also thermo-mechanical parameters is highly desirable. The absence of defects is a figure of merit for the operation conditions that can be applied to the device. Thus, the determination of the structural integrity with a significant accuracy enables a unique selling point: performance will be improved according to the true capabilities of the device to sustain the applied thermal and mechanical load. In sum, today’s hard- and software solutions for in-line testing cannot reach out to the opportunities represented by thermography as established method for industrial application (high TRL) to the point that smart production can be leveraged up to a new level.
Innovation: 100% in-line inspection
INLINETEST proposes a new strategy as well as a new solution for integrating new measurement methods based on transient thermography into the production line for volume manufacturing of micro/nano-electronic components. This approach features novel and world’s first integrable thermographic failure analytical systems for 100% in-line inspection, which is in the focus of the project featuring also other key innovations enabling important aspects for future smart production:
- Exploitation of IR and TR as applied failure analytical method for in-line inspection by exploiting the introspective and physically most justified information of the thermal contrast obtained after pulsed energetic excitation of the component. The method produces already fair single-frame contrast, but reaches full potential by lock-in amplification. Both methods are full-field techniques and are more suitable than scanning techniques to enable fast 100% inspection. For that purpose, the systems feature automated sample feed, positioning, excitation and measurement capabilities.
- Extension of transient thermography to non-contact and reflective surfaces, which are not effectively measurable with infrared techniques but by the complementary method of thermoreflectance. This is highly desirable, as most chips are reflective at the surface in the optical spectrum (metals, semiconductors) where not polymer-passivated. So, both techniques allow monitoring of successive steps in the production process.
- Co-integration of periodic, customizable energetic excitation by various heat sources (radiative, inductive, convective) coupled to lock-in processing and a software environment for data preprocessing, evaluation and decision making respectively.
- High spatial resolution: The methods have the advantage of either mid-IR- or optical resolution (4 μm and 400 nm respectively). This is an advantage over time honored failure analytical techniques, even offline.
Demonstration and benchmarking at the production line under industrial boundary conditions
The in-line inspection systems based on PIRT and TR will be demonstrated at the SMEs and industrial component manufacturer’s at the line in a real industrial environment on a production run featuring a large number of micro/nano-electronic components, exemplified on power multi-chip modules from the industrial sectors of RF systems (GaN) and automotive (Si).
The consortium consists of five companies from three different European countries: Germany, France and Netherlands. Assembled from members along the full value chain from fundamental method development via equipment supplying finally to in-line productions facilites ready to implement new standards in quality assessment.
Berliner Nanotest und Design GmbH
Nanotest, a small enterprise based in Berlin, is a well-established test equipment manufacturer for thermal characterization and failure analysis. They cover characterization of a wide range of materials from electronics industry and also offer thermal analysis of components and systems and sell their measurement systems to customers in various industries. Based on their experience in system development, thermal characterization and reliability assessment they builds the in-line inspection system of project INLINETEST.visit homepage
Thales is a leading European microelectronic components and systems manufacturer and global player and is to test the in-line inspection system on their research production line for RF HEMT components.visit homepage
Technische Universität Chemnitz
The academic side of project INLINETEST is represented by the Technische Universität Chemnitz, who has longstanding expertise in thermal and reliability engineering for test systems in cooperation with industry.visit homepage
Advanced Packaging Center BV
The Advanced Packaging Center is a packaging specialist that develops, proto-types and produces special packaging solutions for the worldwide sensor and power semiconductor market. Advanced packaging Center owns a production line for micro/nano-electronic components and will test the novel equipment under real life conditions.visit homepage
Boschman Technologies BV
The SME Boschman Technologies is a specialist in developing and delivering Film Assist Molding equipment and Ag-sintering equipment for the worldwide semiconductor sensor and power market. Boschman Technologies comes in as an equipment/tool manufacturer to incorporate the envisaged equipment.visit homepage
INLINETEST Website Launched
If you can read this you might probably have stumbled across the first major dissemination activity already. Our Website. This site will be one of our dissemination platforms and be used to provide you with public deliverables, papers and other, additional information. Stay tuned, stay in-line.
INLINETEST on Therminic 2018
Project partner Nanotest has presented their failure analysis ideas, concepts and recent progresses on the largest European conference on thermal phenomena in electronics: Therminic 2018. The conference took place in Stockholm and was hosted by Huawei and SHT. Dan Wargulski, a Nanotest employee, involved in the project, gave compehensive insights in latest achievements in both infrared-based and thermoreflectance-based thermography and discussed the pro's and con's of both methods with regard to failure analysis. The audience mainly consisting of thermal experts gave highly positive feedback and are surely eager to hear about the progress on next year's Therminic conference.