PACKAGING SERVICES

Effective PCB Substrate Design Practices for IC Package Assembly: A Case Study

In the semiconductor package assembly process, achieving precision in substrate design is a crucial element. The substrate should be designed taking into account the ease of assembly. This applies to die attaching, both flip-chip and traditional die attach for wire bonding. In this article, we will look at a specific case study involving shortcomings of a substrate design, focusing on challenges that were faced during the assembly, die attach, and wire bonding stages.

Case Study Overview For COB Substrate Design

Recently, we faced significant challenges during a Chip-on-Board (COB) bonding job involving a two-die configuration. Au wire bonding the primary die was not a path but rather straightforward and encountered no issues. However, the secondary die presented a unique challenge due to the design of the PCB substrate.

Challenges Faced During Au Wire Bonding

Wire Bonding Parameter Optimization To Bond on ENIG-finished Au Vias for Bond Strength

The second die attach pad, or the die attach surface, was designed with Au vias instead of a continuous Au bonding pad covering the full surface like the primary die attach surface with Electroless Nickel Palladium Immersion Gold (ENEPIG) processed surface. Also, the Au vias were not ENEPIG finish but Electroless Nickel Immersion Gold (ENIG), requiring hours of parameter fine-tuning to achieve acceptable bond strength.

Spatial Constraints in Die Downbonding (GND) on Limited Au Via Surface

The primary challenge was the spatial limitation for downbonding from the die; the die itself covered more than 95% of the Au via surface that was supposed to be used for downbonding. Even with minimal epoxy overflow from all sides of the die, less than 150 micrometers, there was not enough exposed surface for downbonding.

Capillary Tool Risks with Restricted Space

Even with the extremely small capillary, high loop size and changing the PCB position and alignment there was no simply enough space to down bond with out the risk of the capillary tool hitting the side wall of the the die casing side wall chipping or even die crack.

 

Strategic Solutions and Best Practices For PCB substrate design

Ensure Die Attach Pad Is Sufficiently Spacious

Ensure that either the Au vias covered or Full Au surfaced die attaches surface is atleast 750um bigger than the die on all sides for down boding the pads at the edge of the die, and if the down bond is from a die pad from the middle or further away from edge of the die, make sure to leave at least 2 times the length of the bond pad to the edge of the die distance to form proper suitable wire loop size. 

Consider Alternative Grounding Options

Strategically place spare bond pads/vias around the die attach surface to cater to errors caused by the die attach/wire bonding mishaps. It is always better to design the substrate for versatility rather than for small substate size for small volume builds for R&D purposes where the main purpose of the build is for proof of concept or specific function testing.

Implement Design for Manufacturability (DFM)

Before sending the pcbdoc/cad files to the PCB manufacturer for substrate fabrication, always involve the assembly engineer or assembly house in general to make sure that die attach and wire bonding can be done as intended. Their experience can inform the design adjustments that accommodate real-world assembly challenges.

 

PCB with a die attached pad barely larger than the die, showing inadequate space for ground connections and high risk of die damage
Challenges in PCB Die Attach: Limited Space and Bonding Risks during bonding.
PCB with gold grounding wire expertly bonded to vias away from the cramped die attach pad to avoid die damage.

Conclusion

The case study presented demonstrates the importance of thoughtful substrate design in semiconductor package assembly. By adopting these best practices, assembly facilities can improve their capability to handle complex packaging scenarios, thereby enhancing overall reliability and efficiency in semiconductor manufacturing. These strategies help in addressing immediate problems and also serve as proactive measures to prevent future issues, ensuring smoother operations and higher quality outcomes in the assembly process.

Please don’t hesitate to contact us for you PCB Substrate Design, PCB Substrate Fabrication and Package Assembly need. 

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What is Chip On Board Technology (COB)?

COB technology simplifies electronic device assembly by placing the microchip directly onto the circuit board. This direct bonding can be achieved through wire bonding or solder bumps. For a deeper understanding of COB’s basics, Electronics Hub offers a comprehensive guide that breaks down the technology and its application.

A Short History of COB

COB technology emerged in the late 20th century as the electronics manufacturing industry sought compact, efficient circuit integration methods. The evolution from surface mount technology (SMT) and through-hole technology (THT) to COB represents a significant leap in manufacturing. Historical insights and the technological progression are well-documented in IEEE’s electronic library.

The Role of COB in Electronics

From LED displays to automotive applications, COB technology has broadened the horizons of electronics manufacturing. Its influence on LED technology, for example, has led to devices that are not only brighter but also more energy-efficient. ScienceDirect publishes research articles detailing COB technology’s impact on the LED industry and beyond.

The Benefits of COB

COB technology brings several advantages to electronic devices, including reduced size and improved thermal management. For those interested in the technicalities of how COB enhances device performance and longevity, the American Society of Mechanical Engineers (ASME) provides resources and papers on thermal management solutions in electronic packaging.

Conclusion

COB technology is at the forefront of driving the electronics industry towards more integrated, efficient, and sustainable solutions. As we advance, the role of COB in fostering innovations in IoT and AI is undeniable. For future trends and insights into COB technology, keeping an eye on TechCrunch’s hardware section can be immensely helpful.

The Ultimate Guide to Wire Bonding Wires

Welcome to the ultimate guide to wire bonding wires. Whether you’re a newbie in the field or a seasoned professional, this comprehensive article has got you covered. In this guide, we will walk you through everything you need to know about wire bonding wires, from their basic concept to the latest advancements in the industry.

Wire bonding is a critical process in semiconductor packaging, enabling the connection between a microchip and its package. But with the wide range of wire bonding wires available, it can be challenging to understand which one is the right fit for your specific application.

That’s why we have compiled a wealth of information in this guide. We will explore the different types of wire bonding wires, their properties, and their applications. We will also dive into the wire bonding process, exploring advanced techniques and troubleshooting common issues that may arise.

Stay tuned as we uncover the secrets of wire bonding wires and unlock the potential for improved performance and reliability in your microelectronic devices. So, let’s begin this journey together and become wire bonding experts!

 

What is wire bonding?

Wire bonding is a crucial technique used in the semiconductor industry to establish electrical connections between microchips and the outside world. It involves using a wire, typically made of gold or aluminum, to create a conductive pathway between the chip and the package. By establishing these connections, wire bonding enables the transmission of electrical signals to and from the microchip.

This process is essential for ensuring the functionality, reliability, and performance of microelectronic devices. Wire bonding provides a low-resistance connection that can withstand the demands of high-frequency signals, temperature variations, and mechanical stress. It is widely used in applications such as integrated circuits, sensors, optoelectronic devices, and more.

The wire bonding process involves three main steps: wire preparation, bonding, and encapsulation. Each step requires precision and careful consideration to achieve optimal results. Let’s delve deeper into the types of wire bonding wires used in this process.

 

Types of wire bonding wires

There are several types of wire bonding wires available, each with its unique properties and advantages. The choice of wire depends on factors such as the application, electrical requirements, and compatibility with the bonding process. Here are the most commonly used wire bonding wire types:

  1. Gold Wire: Gold wire is widely utilized in wire bonding due to its excellent electrical conductivity, corrosion resistance, and stability. It is commonly used in applications that require high reliability, such as aerospace, medical, and automotive electronics. Gold wire bonding offers superior performance, especially in high-frequency and high-power applications.
  2. Aluminum Wire: Aluminum wire is another popular choice for wire bonding, mainly due to its cost-effectiveness. It offers good electrical conductivity and thermal properties, making it suitable for various applications. Aluminum wire bonding is commonly used in consumer electronics, such as smartphones and tablets, where cost is a critical factor.
  3. Copper Wire: Copper wire has gained popularity in recent years due to its superior electrical and thermal conductivity compared to gold and aluminum. Copper wire bonding offers improved performance in terms of signal integrity, power dissipation, and heat transfer. It is commonly used in high-speed data communication, power devices, and advanced packaging applications.

 

Each type of wire bonding wire has its advantages and considerations. The choice depends on factors such as electrical requirements, package design, wire diameter, and bonding process compatibility. Now, let’s explore the materials used in wire bonding wires.

Factors to consider when choosing wire bonding wires

Choosing the right wire bonding wires is crucial for achieving reliable and high-performance wire bonds. Several factors should be considered when selecting wire bonding wires, including:

  1. Electrical Requirements: The wire bonding wire should meet the electrical requirements of the application, such as signal transmission, power dissipation, and impedance control. Factors such as electrical conductivity, resistance, and capacitance should be taken into account.
  2. Package Design: The wire bonding wire should be compatible with the package design and dimensions. Factors such as wire diameter, loop height, and wire length play a crucial role in achieving optimal wire bonds.
  3. Bonding Process Compatibility: The wire bonding wire should be compatible with the bonding process and equipment being used. Factors such as wire material, wire diameter, and bonding technique should be considered to ensure successful bonding.
  4. Environmental Conditions: The wire bonding wire should be able to withstand the environmental conditions of the application, such as temperature variations, humidity, and mechanical stress. Factors such as wire material, corrosion resistance, and thermal properties should be evaluated.

 

By considering these factors, you can make an informed decision when selecting wire bonding wires for your specific application. However, there are common challenges that may arise during the wire bonding process. Let’s explore these challenges and how to overcome them.

Common challenges in wire bonding wires and how to overcome them.

The wire bonding process can be complex, and several challenges may arise that can affect the quality and reliability of the wire bonds. Identifying and addressing these challenges is crucial for achieving successful wire bonds. Here are some common challenges in wire bonding wires and how to overcome them:

  1. Wire Breakage: Wire breakage can occur during the bonding process due to factors such as excessive tension, improper handling, or inadequate wire strength. To overcome wire breakage, it is essential to optimize the bonding parameters, ensure proper wire handling techniques, and use wires with appropriate strength for the application.
  2. Wire Sweep: Wire sweep refers to the lateral movement of the wire during the bonding process. It can occur due to factors such as improper tool alignment, excessive bonding force, or inadequate wire support. To overcome wire sweep, it is crucial to optimize the bonding parameters, ensure proper tool alignment, and use appropriate wire support mechanisms.
  3. Bond Lift-Off: Bond lift-off refers to the detachment of the wire bond from the bonding pad or package. It can occur due to factors such as inadequate bond strength, poor adhesion, or thermal stress. To overcome bond lift-off, it is essential to optimize the bonding parameters, ensure proper surface preparation, and use appropriate bonding techniques and materials.
  4. Oxidation: Oxidation of the wire surface can occur during the wire bonding process, affecting the bond quality and reliability. To overcome oxidation, it is crucial to minimize exposure to air and moisture, ensure proper wire cleaning techniques, and use wires with good oxidation resistance.

 

By addressing these common challenges and implementing the appropriate solutions, you can achieve reliable and high-quality wire bonds. However, there are also best practices that you can follow to optimize the wire bonding process. Let’s explore these best practices.

In conclusion, wire bonding wires play a crucial role in the semiconductor industry, enabling the establishment of electrical connections between microchips and their packages. By understanding the different types of wire bonding wires, their properties, and their applications, you can make informed decisions when selecting the right wire bonding wire for your specific needs.

The wire bonding process and equipment require precision, attention to detail, and specialized knowledge. By following best practices and addressing common challenges, you can achieve reliable and high-quality wire bonds that ensure the performance and reliability of your microelectronic devices.

Whether you’re a beginner or an experienced professional, this ultimate guide has provided you with a comprehensive overview of wire bonding wires. Armed with this knowledge, you can unlock the potential for improved performance and reliability in your microelectronic devices. So, embrace the world of wire bonding wires and become a wire bonding expert!

What is the best IC packaging for PCB?

We all know that optimal performance and reliability of printed circuit boards (PCBs) all comes down to IC packaging.

As experts in IC packaging solution providers, let us help you to choose the best suited IC packaging for your PCB from the wide range of packaging options available, including dual in-line package (DIP), quad flat package (QFP), ball grid array (BGA), and more.

You can thank us later for saving you from a daunting task.

Dual In-Line Package (DIP)

DIP is the oldest and most traditional IC packaging option and they have become quite popular due to their simplicity and cost-effectiveness. DIP packages are ideal for low to medium-density designs and are widely used in various applications due to its distinguishing feature of two rows of pins or leads extending from the sides, allowing for easy insertion into PCBs.

Quad Flat Package (QFP)

QFP is a surface-mount IC packaging option known for its compact size and high-pin count capabilities. It features four sides with leads on each side, allowing for increased pin density and better thermal performance. QFP packages are commonly used in consumer electronics, telecommunications, and automotive industries.

Ball Grid Array (BGA)

BGA is a popular IC packaging option that offers superior electrical and thermal performance. Instead of traditional leads, BGA packages utilize solder balls arranged in a grid pattern on the underside of the IC. This arrangement provides better electrical conductivity, increased pin count, and improved resistance to mechanical stress. BGA packages are widely used in high-density applications, such as microprocessors, GPUs, and memory modules.

Small Outline Integrated Circuit (SOIC)

SOIC is a widely used surface-mount IC packaging option known for its compact size and compatibility with automated manufacturing processes. It features gull-wing leads on two sides, providing excellent electrical performance and efficient heat dissipation. SOIC packages are commonly used in a wide range of applications, including consumer electronics, industrial equipment, and telecommunications.

Chip Scale Package (CSP)

CSP is an advanced IC packaging option that offers a significant reduction in size while maintaining excellent electrical performance. CSP packages have a footprint size similar to the actual IC die, eliminating the need for extra space for packaging. CSP offers high pin counts, low power consumption, and enhanced thermal characteristics, making it ideal for miniaturized devices such as smartphones, wearables, and IoT applications.

When we choose the best IC packaging for your PCB, we carefully consider key factors such as pin count, space constraints, thermal performance, and electrical requirements to ensure the optimal choice that balances performance, reliability, and cost-effectiveness for your PCB.

While we work with common options such as DIP, QFP, BGA, SOIC, and CSP packages we continue to embrace newer packaging technologies that continue to emerge to meet the evolving needs of the electronics industry.

What are the processes involved in wafer fabrication?

The world of semiconductors would not exist without the process that keeps these micro components together! Therefore Wafer fabrication has become a process that is known to all.

Let’s take a look at the general steps of Wafer fabrication that would make you an expert in the industry!

  1. Crystal Growth: Wafer fabrication begins with growing a single crystal ingot of semiconductor material, commonly silicon. This is achieved through a process called the Czochralski method, where a seed crystal is dipped into molten silicon and slowly rotated to pull a larger, single crystal out of the melt. The ingot is then sliced into thin circular discs known as silicon wafers.
  2. Wafer Cleaning: Once the wafers are sliced, they undergo a thorough cleaning process to remove any impurities or contaminants. This typically involves using cleaning solutions, deionized water, and mechanical scrubbing methods to achieve a high level of cleanliness.
  3. Oxidation: Next, the silicon wafers are subjected to an oxidation process. This involves exposing the wafers to high temperatures in the presence of oxygen or steam, forming a thin layer of silicon dioxide (SiO2) on their surface. This oxide layer serves as an insulator and protects the underlying silicon during subsequent fabrication steps.
  4. Photolithography: The process of photolithography is crucial for creating intricate patterns on the wafer’s surface. A light-sensitive material, called a photoresist, is applied to the wafer, and a mask is carefully aligned and placed over it. UV light is then applied, transferring the pattern from the mask to the photoresist. This pattern delineates the areas where subsequent processes will take place.
  5. Etching: Etching is used to remove material selectively from the wafer’s surface according to the pattern defined during the photolithography step. There are two main types of etching techniques: wet etching, which involves dipping the wafer into a chemical solution, and dry etching, which utilizes plasma to remove material. These processes are vital for creating features such as transistors, interconnects, and contact points.
  6. Deposition: Deposition involves adding layers of various materials, such as metals or insulators, onto the wafer’s surface. There are different methods of deposition, including chemical vapor deposition (CVD), physical vapor deposition (PVD), and atomic layer deposition (ALD). These techniques allow for the precise formation of thin films to enhance conductivity, insulation, and other necessary properties.
  7. Doping: To modify the electrical properties of specific regions on the wafer, dopants (impurities) are introduced. This process, known as doping, involves diffusing specific atoms, such as boron or phosphorus, into the silicon lattice. Doping is essential for creating various types of transistors, diodes, and other semiconductor devices on the wafer.
  8. Annealing: After deposition and doping, the wafers go through an annealing process. Annealing involves subjecting the wafers to high temperatures to activate the dopants and fully recover any crystal damage caused during the previous steps. This helps stabilize the wafer’s electrical properties and ensures reliable performance of semiconductor devices.

Yes! You guessed right! Wafer fabrication is a complex and meticulously controlled process, involving multiple steps that transform a simple silicon wafer into a sophisticated electronic component. Through understanding these processes contribute effectively to the development of advanced electronic devices we rely on today!

What Is IC Packaging & Why Is It Important?

Need we explain what happens if the circuit design is not secured properly? Yes, you waste your entire effort and also the hassle to redo. Not to mention how your clients are not going to be happy either!

Therefore, let’s look at one of the most important processes in the world of electronics!

Semiconductor packaging or IC packaging!

What is IC Packaging?

IC packaging, or integrated circuit packaging, refers to the process of protecting and enclosing integrated circuits within a protective covering. It involves assembling and enclosing electronic components, such as the silicon chips, into packages that provide electrical connectivity and mechanical support. 

IC packaging is the crucial step that transforms the fragile ICs into sturdy, reliable, and easily usable devices.

Why is IC Packaging Important?

Protection and Reliability

Ofcourse! The most obvious importance of IC packaging is  protection against physical damage, moisture, dust, and other environmental factors that could potentially harm the delicate ICs. Furthermore, it enhances the longevity and performance of the electronic devices, making them more reliable in diverse operating conditions.

Seamless Electrical connectivity

IC packaging incorporates the connections of various contact pins, leads, or terminals that establish electrical connections between the IC chip and other components, such as circuit boards or connectors. These connections enable efficient flow of electrical signals, power, and data, ensuring seamless communication within electronic systems.

Miniaturization and Size Reduction

IC packaging massively contributes to miniaturization in the electronics industry. This compactness enables the creators to meet the demands of the modern day customer ; making the electronic devices smaller, sleeker, and easily portable. 

Effective Thermal Management

The IC packaging solutions help manage the heat generated during normal operations, dissipating it efficiently to prevent damage and maintain optimal performance. Therefore, thermal management effectively will help you to extend the lifespan of ICs and reduce the risk of failure due to overheating.

High-Speed Performance

IC packaging plays a crucial role in maximizing the electrical performance of integrated circuits. Carefully designed packages minimize signal degradation, power losses, and electromagnetic interference (EMI), enabling high-speed communication and reducing latency in electronic systems. This is especially critical in applications like telecommunications, automotive, and high-performance computing.

Product Differentiation and Customization

Different package types and styles offer companies the flexibility to tailor their products according to specific requirements, target markets, and applications. By partnering with the ideal IC packing solution provider, manufacturers can enhance their product’s functionality, reliability, and overall appeal to consumers.

It is inevitable that IC packaging helps in addressing a lot of critical challenges faced by the electronic manufacturers today. However, choosing a CREDIBLE IC PACKAGE SOLUTION PROVIDER is the ONLY way to make informed decisions to create superior, efficient, and innovative electronic devices, driving progress in the field of technology.

Contact us today to further explore what our IC packaging solutions could expand the horizon of your business.