Advanced packaging technology solution: breaking through performance bottlenecks and empowering future semiconductor development

Overview

As semiconductor manufacturing processes gradually approach physical limits, the traditional path of improving chip performance by shrinking transistor sizes has become unsustainable. Moore's Law states that the number of transistors on an integrated circuit doubles approximately every 18 to 24 months; in other words, processor performance doubles roughly every two years while the price drops by half. However, as transistors edge closer to atomic dimensions, further miniaturization faces immense technical challenges and cost pressures. Against this backdrop, Advanced Packaging has emerged as a key driver to extend Moore's Law and fuel the sustained development of high-performance computing, artificial intelligence, 5G communications, automotive electronics, and other sectors. Beyond its traditional role of "protecting chips", it serves as a core means of system-level performance optimization. Through heterogeneous integration, high-density interconnection, and advanced material processes, it achieves comprehensive breakthroughs in chip performance, power consumption, area, and cost (PPAC). Its growing technical complexity and strategic value are reshaping the competitive landscape of the global semiconductor industry.

 

This paper systematically elaborates on current advanced packaging technology solutions from four dimensions: technical architecture, core schemes, key challenge mitigation, and industrial development trends, while conducting an in-depth discussion on their technical details, industrial impact, and future directions.

 

Core Technical Architecture and Classification: Restructuring Interconnection Paradigms to Break Physical Boundaries

Advanced packaging reshapes inter-chip connection methods and enables system-level integration through four core elements: RDL (Redistribution Layer), TSV (Through-Silicon Via), Bump, and Wafer.

 

Its main technical routes include the following:

1.  2.5D Packaging: Cornerstone of High-Bandwidth Interconnection

    It uses a silicon interposer as an intermediate bridge to integrate multiple chips (e.g., GPU, HBM) side-by-side in a single package, significantly shortening signal paths and improving data transmission efficiency.

    Advantages: Compared with traditional packaging technologies, 2.5D packaging has distinct differentiated advantages in cost, performance, and application scenarios. First, in terms of cost, 2.5D packaging effectively reduces overall costs by optimizing chip layout and minimizing material usage. Second, in terms of performance, its high-bandwidth and low-latency characteristics make it outstanding in handling large-scale data and high-speed computing tasks, and it is widely used in AI training, high-performance computing, and other fields. For example, NVIDIA's H100 GPU integrates 8 HBM3 chips via CoWoS packaging, achieving a bandwidth of 3.35 TB/s, an increase of over 50% compared with the previous generation. Third, in terms of application scenarios, the flexibility and scalability of 2.5D packaging enable it to meet the needs of different fields such as data centers and autonomous driving.

2.  Fan-Out Packaging and System-in-Package (SiP): Miniaturization Tools for Multi-Chip Integration

    - Fan-Out Packaging breaks through pin count limitations and supports wider solder ball pitches (e.g., RDL layer pitch reduced to 20 μm), making it suitable for high-I/O demand scenarios (such as mobile phone SoCs).

    - SiP integrates heterogeneous chips including processors, memory, and RF modules into a single package, reducing system cost and size. For example, Apple Watch adopts SiP packaging to integrate dozens of chips into a space the size of a fingernail. SiP packaging offers advantages of low cost and flexible design, but its performance is relatively modest, making it ideal for cost-sensitive consumer electronics products with space constraints.

3.  Chiplet Modular Design: A Lego-Style Revolution for Cost Reduction and Efficiency Improvement

    It splits large chips into multiple small chips (chiplets), which are manufactured separately and then integrated via advanced packaging. For instance, AMD separates CPU cores from I/O modules using Chiplet technology and adopts TSMC's CoWoS-S packaging, achieving a 30% performance boost while cutting costs by 15%.

    Standardization Drive: The UCIe (Universal Chiplet Interconnect Express) Consortium (whose members include Intel, AMD, Qualcomm, etc.) has formulated unified interface standards to accelerate the development of the Chiplet ecosystem. It is expected that the global Chiplet market size will exceed 10 billion US dollars by 2027.

 

Key Technical Solutions and Innovative Breakthroughs: Overcoming Process Challenges to Empower Ultimate Performance

1.  Flip Chip Package Structure Optimization: Dual Improvement of Reliability and Efficiency

    - Core Issues: Encapsulant shrinkage causes chip warpage and bonding misalignment, affecting reliability and signal integrity.

    - Innovative Solutions:

      - High-Temperature Resistant Buffer Structure: High-strength materials such as phenolic resin and PEEK (polyether ether ketone) are introduced to form a 0.1–0.3 mm isolation layer, effectively suppressing warpage. For example, a power device integrated with a PEEK buffer layer reduced warpage from 80 μm to 15 μm. In the automotive electronics field, this technology has significantly improved the stability of Engine Control Units (ECUs).

      - Integrated Flip Chip Bonding Process: Multi-chip units are bonded simultaneously, and through conformal mold design, bonding efficiency is doubled and yield is increased by 15%. This process is widely adopted in 5G base station construction to ensure stable and low-loss high-frequency signal transmission.

      - Process Improvement: A segmented encapsulant injection technology is adopted (injected in three stages with gradient temperature curing: 120°C → 150°C → 180°C), reducing air bubbles and internal stress. The hardness of the package is increased by 20%, with a bending strength of up to 300 MPa. In consumer electronics, this technology has improved the durability and drop resistance of smartphone motherboards.

2.  High-Density Interconnection and Automatic Routing Tools: Empowered by Intelligent Design

    It supports large-scale automatic routing for multi-chip systems such as HBM and UCIe, optimizing signal paths and power distribution. It integrates cross-process physical verification functions (e.g., hybrid simulation of silicon interposers and organic interposers) to adapt to different material characteristics. A built-in DFM (Design for Manufacturability) rule engine automatically detects routing density and spacing violations, improving design efficiency by 40%. It addresses the challenges of complex routing and difficult signal integrity assurance in multi-chip heterogeneous integration, supporting the development of TSMC's 3nm process node packaging.

3.  Bubble Control and Reliability Enhancement: Precision Engineering in the Microscopic World

    - Key Challenge: Air bubbles are prone to form during underfilling, chip bonding, and other processes, leading to poor heat dissipation (30% increase in thermal resistance), signal interference (impedance fluctuations), and connection failure.

    - Mainstream Deaeration Technologies:

      - Vacuum-Pressure Alternating Technology: By intelligently regulating temperature and pressure parameters (e.g., cyclic switching between 0.1 Pa vacuum and 5 MPa pressure), air bubbles are driven out and the encapsulant is compacted.

      - Soft Cushion Airbag Lamination Technology: Replacing traditional roller lamination, it adapts to uneven surfaces and increases filling rate to 99.5%.

      - Multi-Stage Intelligent Deaeration Process: Customized vacuum/pressure cycle programs (e.g., 5 cycles of 10 minutes each) are designed based on material properties (such as epoxy resin curing curves).

 

Key Challenge Mitigation: Bridging the Gaps in Technology, Cost, and Ecosystem

1.  Thermal Management and Heat Dissipation Bottlenecks

    Multi-layer stacking in 3D packaging leads to heat concentration, and traditional heat dissipation solutions (such as thermal interface materials) are insufficient to meet demand.

    Solutions:

    - Microchannel Liquid Cooling Technology: Microchannels (100 μm in diameter) are embedded inside the package, and heat is removed through liquid metal circulation, reducing thermal resistance by 70%.

    - Diamond Heat Dissipation Layer: A diamond film (with a thermal conductivity of 2000 W/m·K) is deposited on the chip surface to improve heat dissipation efficiency.

    - Thermal Simulation and Optimization: AI algorithms are used to simulate heat distribution and optimize chip layout and heat dissipation paths.

2.  Yield and Cost Control

    - Challenge: Processes such as TSV and hybrid bonding are yield-sensitive, resulting in high costs. Industry data shows that every 1% increase in yield can reduce costs by approximately 5%.

    - Mitigation Strategies:

      - Process Optimization: Low-temperature bonding technology (<200°C) is developed to reduce thermal stress damage; laser drilling replaces mechanical drilling to improve TSV precision.

      - Testing Technology Upgrade: X-ray computed tomography (CT) and acoustic microscopy are introduced to enable early defect detection. One enterprise reduced production costs by 10% by detecting defects early using this technology.

      - Supply Chain Collaboration: An integrated platform for chip design, manufacturing, and packaging/testing is established to reduce iteration costs. In practice, the application of the integrated platform has shortened the product iteration cycle by 20% and saved costs by 8%.

3.  Standard and Ecosystem Fragmentation

    The Chiplet ecosystem lacks unified standards, with diverse interface protocols and packaging specifications that restrict industrial collaboration.

    - Solutions:

      - Promote the implementation of UCIe standards to achieve cross-vendor Chiplet interoperability.

      - Establish an open-source Chiplet design library to lower development barriers.

 

Industrial Impact and Development Trends: Reshaping the Semiconductor Industry Landscape