Wire Bonding in Altium Designer

Introduction

Wire bonding technology has evolved significantly over the years and so has its use cases and applications. As devices become more compact and powerful, designers need precise tools to handle complex interconnects, and Altium Designer has responded with capabilities that streamline wire bonding for Chip-on-Board (COB) designs, stacked dies in cavity, and other high-performance applications. This article explores the advanced wire bonding features in Altium Designer and how they ensure reliability.

Advanced Wire Bonding Techniques in Altium Designer

Altium Designer’s wire bonding tool offers a range of new capabilities, making it easier to incorporate advanced bonding techniques into PCB designs. Let’s take a look at some of the standout features:

• Wire Bonding for Stacked Die in Cavity: Users can now easily handle the complex interconnects required for stacked dies within a cavity structure, also known as 3D integrated circuits. By utilizing the Rigid & Flex Advanced Mode in the Layer Stack Manager, dies structures and die pads can be easily drawn and placed on different stackups to create a 3D structure. Altium Designer’s capability to visualize wire bonds In 3D view allows designers to ensure that wire bond loop heights, lengths, diameter and paths are optimized for the design's electrical and mechanical requirements. These 3D visualizations are crucial when managing the fine pitch and high pin counts typical of stacked die structures used in advanced computing and mobile devices.

Wire bonding stacked die in the cavity (3D Integrated Circuit)

• Die-to-Die Wire Bonding: Altium Designer’s Wire Bonding tool allows for die-to-die wire bonding, a technique used to minimize parasitic inductance and signal interference. Multiple dies can be directly connected with wire bonds without requiring intermediate fingers pads or copper pours, reducing loop length and optimizing performance for high-frequency and high-power applications.

Die-to-die wire bonding

• Wire Bonding Die to Copper Pour: In many power electronics and high-current applications, connecting the die directly to a copper pour is essential for effective thermal and electrical performance. Altium Designer Wire Bonding tool supports this by enabling precise wire bonding between the die and a copper pour area on the PCB. This method is particularly useful in high-power designs, such as power management modules, where heat dissipation and current handling capabilities are critical. By allowing the connection of bond wires directly to large copper pours, designers can ensure that the electrical and thermal performance is optimized, reducing the need for additional interconnects and vias.

Multiple wire bonds on copper pours

• Multiple Wire Bonds for the Same Die Pad: Altium Designer Wire Bonding tool also supports multiple wire bonds from the same die pad to enhance current-carrying capacity and reduce impedance. This technique is particularly important in power electronics and high-performance applications, where higher currents flow through the die, necessitating additional wire bonds to distribute the electrical load. Multiple wire bonds also improve mechanical reliability by reducing the stress on individual wire bonds, enhancing both thermal and electrical performance in high-stress environments.
• Pad Alignment and Orientation: Proper pad alignment and orientation are crucial for a successful wire bonding process. Altium Designer’s Wire Bonding tool can batch align finger pads with the direction of the bond wires, ensuring minimal bond loop lengths and reducing the risk of mechanical stress or misalignment during manufacturing. This feature helps optimize wire bond placement, improving both electrical performance and bond integrity, especially in complex and high pin count designs.

Finger pad alignment with wire bond direction

Wire Bond Specifications and Design Flexibility in Altium Designer

Altium Designer’s Wire Bonding tool allows for a high degree of flexibility in configuring wire bonding specifications to meet precise design requirements. These capabilities help optimize the bond for both electrical performance and manufacturing efficiency. Some of the key adjustable parameters include:

• Wire Diameter, Bond Type, and Loop Height Adjustments: Altium Designer enables designers to fine-tune wire diameter, bond type, and loop height for each wire bond. Whether the design requires thicker wires for power applications or finer wires for high-density signal interconnects, these parameters can be easily adjusted within the software’s interface. This flexibility is crucial in achieving the desired electrical performance and mechanical stability, especially in applications like power electronics or high-resolution image sensors:

  • Wire Diameter: Designers can specify the diameter of the bond wire based on current-carrying capacity and space constraints.
  • Bond Type: Both: wedge bonding and ball bonding are supported, allowing designers to choose the best bonding method depending on the design requirements.
  • Loop Height: Precise control over loop height helps optimize the mechanical stability of the bond wire while minimizing signal interference and parasitic inductance, which is critical for high-speed designs.

Wire bonds properties panel

• Generating Output Reports and Draftsman Drawings: Altium Designer can now generate detailed output reports and Draftsman drawings that include all wire bonding details. This includes documentation of wire bond connections, die pad names, bond wire lengths, and bonding types. These reports can be formatted in CSV or included as part of fabrication drawings, ensuring clear communication with manufacturers and wire bonding service providers. The Draftsman tool within Altium Designer also supports wire bonding elements, such as bond wire placement and die layout, allowing for comprehensive assembly documentation. These reports are crucial for ensuring that wire bonding specifications are accurately communicated and adhered to during manufacturing, thereby improving production yields and reducing the risk of errors.

Ensuring Reliability and Design Success

Altium Designer Wire Bonding tool is designed to address the key challenges in ensuring the reliability and success of wire bonding designs, and minimizing and detecting any design errors. This is achieved as follows:

• New Wire Bonding Design Rule Checks (DRC) & Query Language Keywords: A new DRC specifically for wire bonding is now available. Designers can set specific rules for wire bond clearances, wire-to-wire spacing, and bond lengths. Additionally, two new query language keywords “IsBondFinger” and “IsBondWireConnected” can be used in combination with other keywords to create advanced design rules to cover any wire bonding layout and configurations. Altium Designer will automatically flag any violations, ensuring that bond wires meet stringent manufacturing and reliability standards.

Flagged violation in 3D view

Example of a clearance rule violation between two finger pads

Example of a clearance violation between a finger pad and a copper pour

• 3D Visualization and Validation: Altium Designer’s 3D visualization capabilities now also include die bodies, die pads and wire bonds. Designers can view wire bonds in relation to the entire PCB design, adjusting wire paths, lengths, and loop heights to avoid mechanical issues. This real-time validation ensures that wire bonding connections are secure and reliable throughout the design and manufacturing process.

Wire bonds can be visualized in 3D, length measurements can be accessed in the properties panel

Conclusion

Altium Designer offers an array of advanced features that enable precise and reliable wire bonding in today’s most demanding applications. From stacked dies in cavity to die-to-die bonding and high-power applications, Altium Designer’s comprehensive tools ensure that wire bonding can meet the growing needs of modern electronics. By enabling advanced techniques such as multiple wire bonds, pad alignment, and die-to-copper bonding, Altium Designer allows engineers to optimize both performance and reliability in their designs.

If you want to learn more about the Wire Bonding feature and the new functionalities coming in Altium Designer 25, we invite you to join our November webinar: Modernizing Engineering Workflows: Altium Designer 25 and the Future of Concurrent Design.

Additionally, you can start your free trial of Altium Designer + Altium 365 today and discover how to take your PCB designs to the next level.