STI Electronics Engineering
Material Failure Analysis
- Qualification testing
- Visual Inspection & IPC Compliance Testing
- Residue/cleanliness analysis
- Solderability Testing.
The experience and knowledge of STI’s Analytical Laboratory personnel enables interpretation of test results and reporting that lets our customers make the right choices for corrective actions. STI’s enhanced capabilities are the result of the recent addition of several new analytical tools and equipment. The analytical equipment includes some of the industry’s newest and most advanced tools. STI also provides services as an expert witness and arbitrator.
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Qualification Testing
- Visual Inspection: Examination of the physical structure for any defects or anomalies.
- Plating Surface Evaluation (SEM/EDS): Analysis using Scanning Electron Microscopy and Energy Dispersive Spectroscopy to inspect surface composition and quality.
- Plating Thickness Evaluation (XRF): Utilization of X-ray fluorescence to measure the thickness of plating.
- Ionic Cleanliness Testing (IC): Assessment of ionic residue on electronic assemblies to ensure cleanliness and prevent corrosion.
- Environmental Testing: Tests conducted under various environmental conditions to verify durability and functional reliability.
Excerpt Title: Key Aspects of Qualification Testing for PCBs and PCBAs
Qualification testing validates that printed circuit boards (PCBs) and electronic assemblies (PCBAs) adhere to quality standards and specifications. Below are essential components of the testing process:
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Visual Inspection / IPC-Compliance
Visual Inspection and IPC Compliance testing are critical for ensuring that both bare printed circuit boards (PCBs) and electronic assemblies (PCBAs) meet specific industry and customer specifications. Here's a breakdown of the process:
- Visual Inspection on PCBs: Evaluates the physical appearance of bare boards to ensure they comply with standards such as IPC-A-600, or specific customer criteria.
- IPC Compliance for PCBs: Confirms that the PCBs adhere to the minimum requirements set forth by relevant IPC standards or custom specifications.
- Visual Inspection on PCBAs: Assesses electronic assemblies visually to check conformance with standards like IPC-A-610 or customer-specific criteria.
- IPC Compliance for PCBAs: Verifies that the assemblies meet all specified compliance criteria under the IPC-A-610 standards or other designated specifications.
Visual Inspection and IPC Compliance Testing for PCBs and PCBAs
This inspection ensures that both PCBs and PCBAs meet essential quality and reliability standards before being used in further applications.
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(SEM) & (EDS)
Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) are powerful tools for the inspection and analysis of electronic components, including PCBs and PCBAs. Below are the key features and applications of these technologies:
- Scanning Electron Microscopy (SEM): Provides high-magnification visual inspection and dimensional measurements of electronic components. SEM can magnify thousands of times beyond traditional optical microscopes, offering high depth of field and detailed imaging, ideal for failure analysis and quality assurance.
- Secondary Electron Imaging: Utilized for surface topography mapping, this method is effective in analyzing fracture surfaces, integrated circuit surfaces, MEMs, and external plating. It provides detailed insights into the surface structures and anomalies.
- Backscattered Electron Imaging: Allows for imaging based on atomic number contrast, useful in contamination analysis, elemental phase identification, and surface quality evaluations. It is crucial for assessing material composition and detecting phase boundaries.
- Energy Dispersive Spectroscopy (EDS): Enables qualitative and quantitative elemental analysis at the microscopic level. EDS can be used to identify and map elements within a material, supporting efforts in materials selection, residue analysis, and corrosion identification.
Utilizing SEM and EDS for Detailed Material Analysis in Electronics
These technologies are essential in electronic manufacturing for ensuring material integrity, aiding in root cause analysis, and enhancing product reliability through detailed microscopic examinations.
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Ion Chromatography (IC)
- Ion Chromatography (IC): Measures ionic activity, including anions, cations, and weak organic acids, in solvent extracts from samples. Results are presented in micrograms per square inch (μg/in²).
- IPC-TM-650 Compliance: Performed in accordance with the IPC-TM-650, Method 2.3.28, specifically designed for "Ionic Analysis of Circuit Boards, Ion Chromatography Method."
- Applications: Suitable for both bare boards (PCB) and electronic assemblies (PCBA), ensuring cleanliness and compliance with industry standards.
Ion Chromatography for Electronic Component Cleanliness
Ion Chromatography (IC) or Ionic Cleanliness testing is essential for assessing the cleanliness of electronic components such as PCBs and PCBAs. It involves a detailed analysis using a conductivity detector to measure ionic contaminants extracted from the components. This process adheres to the stringent IPC-TM-650, Method 2.3.28, ensuring each component's compliance with industry cleanliness standards. The technique not only provides quantitative data on ionic contaminants but also supports manufacturers in addressing cleanliness-related issues through expert consultation and real-world experience.
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Transmission X-Ray Analysis
- Ball Collapse in Ball Grid Arrays (BGA): Identifies collapses within the solder balls of BGAs.
- Open Solder Connections: Detects unconnected solder points that should be linked.
- Void Inspection: Examines the presence of voids within solder joints.
- Solder Bridges Between Adjacent Conductors: Identifies unwanted solder connections between close conductors.
- Gold Wire-Bond Evaluation: Assesses the integrity of gold wire bonding in microelectronics.
- Through-Hole Barrel Fractures: Detects fractures within the barrels of through-hole components.
- Internal Annular Ring Registration: Inspects the alignment and registration of internal annular rings.
- PCB Trace Inspection: Checks the continuity and quality of printed circuit board traces.
Transmission X-Ray Evaluation for Circuit Board Quality Assurance
Real-time transmission x-ray analysis provides immediate, non-destructive imaging of various electronic components, from micro ball grid arrays to large circuit board assemblies up to 18 inches by 21 inches. This method captures high-resolution, digitally projected images or produces photo-quality prints to suit detailed analysis needs. With capabilities for magnifications up to 125 times, transmission x-ray can inspect features as minute as individual wire bonds and flip chip ball interfaces, facilitating thorough internal defect characterization and quality control.
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Micro-Sectioning Analysis
- On-site Services: Provides convenient and fast micro-sectioning and sample preparation directly on-site.
- Failure Site Location: Identifies the specific site of a failure within a component or assembly.
- Root Cause Identification: Determines the exact failure mechanism and underlying causes through detailed analysis.
Micro-Sectional Analysis for In-Depth Failure Investigation
Micro-sectional analysis is a crucial technique in electronics manufacturing for identifying and understanding the root causes of component failures. This process involves precise on-site micro-sectioning and sample preparation, which allows for a quick turnaround in failure analysis efforts. Once a failure site is accurately located, the subsequent detailed examination helps pinpoint the exact mechanisms and causes of the failure, aiding in corrective measures and enhancing product reliability.
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XRF - Plating Thickness Evaluation
- Non-destructive Measurement: Utilizes X-Ray Fluorescence Spectroscopy (XRF) to measure plating thickness without damaging the sample.
- Versatile Application: Applicable to various plating finishes including tin-lead (Sn-Pb), immersion silver (ImAg), immersion tin (ImSn), electroless nickel immersion gold (ENIG), and thick gold (Au).
- Applicability to Different Conductors: Capable of measuring plating thickness on both large and fine-pitch conductors.
XRF for Precise Plating Thickness Evaluation in Electronics
X-Ray Fluorescence Spectroscopy (XRF) is a powerful tool for ensuring the quality of printed circuit boards and electronic components through precise, non-destructive measurement of plating thickness. This technique is versatile enough to handle a wide range of plating finishes such as tin-lead, immersion silver, immersion tin, electroless nickel immersion gold, and thick gold. XRF provides critical data on the thickness of these finishes, applicable to both large and fine-pitch conductors, facilitating stringent quality control in electronics manufacturing.
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Wetting Balance Testing
- Quantitative Assessment: Measures the wetting forces between molten solder and a test surface over time to quantitatively assess solderability.
- Wetting Force Dynamics: Tracks the change in wetting force from negative (non-wet condition) to positive, indicating successful solder wetting.
- Solderability Parameters: Evaluates the time taken for wetting to occur, crucial for determining component solderability.
- Applicable Standards: Conducts testing in compliance with IPC J-STD-002, IPC J-STD-003, or Mil-Std-883 specifications.
- Versatile Component Testing: Suitable for both leaded and non-leaded surface mount (SMT) and through-hole (PTH) components, using either leaded or lead-free solder.
Wetting Balance Testing for Enhanced Solder Quality Analysis
Wetting balance testing is an essential method for determining the solderability of electronic components. It involves a precise, quantitative evaluation of how solder interacts with component surfaces, measuring the wetting forces over time to identify whether a surface exhibits good solder wetting characteristics or suffers from non-wetting or dewetting issues. This method is crucial for ensuring high-quality soldering in manufacturing processes, adhering to industry standards like IPC J-STD and Mil-Std. Wetting balance testing helps in optimizing manufacturing practices and ensuring the reliability of electronic assemblies.
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FTIR - Organic Contamination Testing
- Chemical Bond Identification: Utilizes the unique absorption wavelengths of chemical bonds to identify organic and inorganic substances.
- Molecular Fingerprinting: Treats the FTIR spectra of compounds as unique identifiers, akin to molecular "fingerprints."
- Quantitative Analysis: Capable of quantifying components within unknown mixtures through detailed spectral analysis.
- Application in Contamination Testing: Particularly useful for identifying substances such as fluxes, cleaners, coatings, and contaminants.
- Reference Library Comparison: Compares spectra of unknown substances with a comprehensive library of known materials used within the industry.
FTIR Testing for Organic Contamination Analysis
Fourier Transform InfraRed Spectroscopy (FTIR) is a powerful analytical tool in electronics manufacturing for detecting and identifying organic and inorganic contaminants. By analyzing the types of chemical bonds and their absorption wavelengths, FTIR provides a precise "molecular fingerprint" of materials. This capability is crucial for identifying various substances, including fluxes, cleaners, and coatings, ensuring that products are free from unwanted organic contaminants. FTIR's ability to quantitatively analyze mixtures and compare unknown substances against a well-established reference library makes it invaluable for maintaining high standards of purity and compliance in manufacturing processes.
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Dye & Pry Testing
- Dye Penetration Method: Uses a low-viscosity dye that penetrates fractures under high vacuum conditions.
- Vacuum and Bake Process: Involves applying a vacuum for several hours, followed by a high-temperature bake to cure the dye.
- Mechanical Removal and Inspection: After curing, the component (e.g., BGA or QFN) is removed to inspect the pad surfaces for dye traces.
- Fracture Identification: Intact bonds repel the dye, but fractured surfaces are stained, indicating solder joint failures.
Dye and Pry Testing for Detecting Solder Joint Failures
Dye and Pry testing is a critical diagnostic method used to identify failures in solder joints, particularly in ball grid array (BGA) and quad flat no-lead (QFN) components. The technique relies on the ability of a specially formulated dye to seep into any existing cracks or fractures under the influence of a high vacuum. After the dye application, components undergo a high-temperature curing process, followed by mechanical removal. This allows for a detailed inspection of the dye's presence on the pads, revealing any compromised joints. Dye and Pry is an effective approach for confirming the integrity of solder connections in complex electronics.
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Supply Chain Validation
- Component Origin Analysis: Determines the origins of components and materials to identify counterfeit or altered items.
- Malicious Intent Detection: Works with software and firmware partners to detect and resolve malicious activities within systems.
- Supply Chain Optimization: Utilizes a phased project plan to transition from detection to establishing a trusted supply chain.
- Phased Project Implementation:
- Phase I: Develops the prototype scenario, requirements specification, and detailed project plan including deliverables.
- Phase II: Implements the prototype, addresses design and manufacturing risks, and documents lessons learned for broader application.
- Phase III: Expands the prototype across commercial and governmental sectors to establish a compliance model for the supply chain.
Supply Chain Validation for Electronics and Electromechanical Assemblies
STI Electronics employs advanced testing and analysis methods to validate the integrity of the supply chain for electronic and electromechanical assemblies. This rigorous validation process helps pinpoint the origins of all components to guard against counterfeit or modified parts, ensuring the overall security and reliability of the supply chain. Through collaboration with software and firmware experts, STI also identifies and mitigates potential threats at the system level. The approach is structured around a comprehensive, phased project plan, designed to progressively build a secure and trusted supply chain while sharing valuable insights with the broader Trusted Systems and Networks community, encompassing both DoD and commercial sectors. This systematic method not only enhances supply chain security but also sets a standard for compliance across the industry.
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