Direct Bond Interconnect Architecture for Fine-Pitch Chip Packaging
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Solution Overview
Problem
Existing semiconductor chip packaging technologies face challenges in achieving high-density interconnects with small pitch sizes, leading to difficulties in assembly yields and reliability due to material interactions, precision requirements, and increased complexity in power delivery and manufacturing costs, especially in high-performance computing applications.
Innovation Solution
Employing solderless direct metal-to-metal interconnects with a dielectric polymer region between semiconductor chips and package substrates, utilizing copper or gold connections and polymers like polyimides or benzocyclobutene, to form direct bond interconnects without solder, allowing for tighter pitch connections and improved assembly yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If solderless direct metal-to-metal interconnects are used, then manufacturing precision and assembly yields improve, but material interaction control and process complexity increase
Solution Approach 1:
A dielectric polymer layer is introduced as an intermediary between the metal interconnects and the surrounding environment. This polymer layer controls material interactions by providing a stable dielectric barrier, while the metal-to-metal bonding process itself maintains high precision through direct atomic contact without solder intermediaries. The polymer mediator thus enables precise metal bonding while controlling overall material compatibility.
Solution Approach 2:
The patent replaces the traditional solder-based mechanical bonding system with a direct metal-to-metal diffusion bonding system. This substitution eliminates the need for solder materials and associated reflow processes, achieving higher manufacturing precision through controlled diffusion bonding at elevated temperatures. The process complexity increases due to the need for precise temperature and pressure control, but assembly yields improve through elimination of solder-related defects.
2Quantity of substance
If tighter pitch connections are implemented, then interconnect density improves, but reliability and assembly difficulty worsen
Solution Approach 1:
The patent changes the bonding parameters by using direct metal-to-metal diffusion bonding at elevated temperatures (e.g., 400-600°C) without solder. This parameter change enables tighter pitch connections by allowing atomic diffusion across smaller gaps, achieving higher interconnect density. The reliability is maintained through the formation of strong metallic bonds that are inherently more reliable than solder joints, especially at fine pitches where solder joint integrity becomes problematic.
Solution Approach 2:
The patent employs a composite structure consisting of metal interconnects embedded in a dielectric polymer matrix. This composite approach allows tighter pitch connections by providing mechanical support and electrical isolation through the polymer while maintaining direct metal-to-metal contact for electrical connection. The combination of materials enables high density interconnects with improved reliability compared to traditional solder-based approaches.
3Stability of the object's composition
If solderless interconnects are used, then thermal stability improves, but manufacturing process complexity increases
Solution Approach 1:
The patent utilizes phase transitions in the dielectric polymer material during the bonding process. The polymer undergoes transitions from a rigid state at room temperature to a softened state at bonding temperatures, enabling metal-to-metal contact and diffusion. This phase transition approach provides thermal stability by allowing the process to proceed through controlled temperature stages, while the increased process complexity arises from the need to precisely control these thermal phases.
Solution Approach 2:
The patent changes physical parameters including temperature, pressure, and time to achieve direct metal bonding. Temperature is elevated to enable diffusion bonding, pressure is applied to ensure intimate metal contact, and time is controlled to achieve adequate bond strength. These parameter changes improve thermal stability by creating strong metallic bonds that withstand thermal cycling, while increasing process complexity due to the need for precise control of multiple parameters simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables reliable and efficient high-density interconnects with reduced pitch sizes, enhancing assembly yields and reducing manufacturing complexities while maintaining thermal stability and compatibility with advanced computing systems.
Implementation Method 1
a region between the at least two semiconductor chips and the package substrate wherein the region comprises a dielectric polymer
Implementation Method 2
solderless metal-to-metal interconnects, wherein the solderless metal-to-metal interconnects operably connect the at least two semiconductor chips to the package substrate
Data Source
AI summary
Assemblies and methods of manufacturing assemblies comprising semiconductor chips and package substrates wherein the semiconductor chips are operably coupled to the package substrate through a solderless direct metal-to-metal bond region. The solderless direct metal-to-metal bond region also comprises a dielectric polymer. Package substrates can comprise interconnect bridges and the semiconductor chips can be operably coupled to the interconnect bridges and can also be operably coupled to each other through the interconnect bridges.