芯片互联，复杂性飙升

Core Viewpoint - The article discusses the evolution of interconnect complexity in semiconductor design, highlighting the transition from traditional two-level routing structures to more complex five-level systems, which enhance flexibility but also increase design challenges and costs [1][25]. Group 1: Evolution of Interconnect Structures - Historically, interconnect structures in integrated circuits (IC) and printed circuit boards (PCB) have been limited to two levels, but recent advancements have expanded this to five levels, significantly increasing complexity and decision-making requirements [1][25]. - The distinction between chip-level and PCB-level design has been significant, with chip designers focusing on internal wiring and PCB designers managing connections to other components [3][25]. Group 2: Challenges in Chip Design - Three key trends are challenging traditional interconnect solutions: the importance of signal transmission lines, increased power levels leading to heat dissipation issues, and higher chip integration levels that exacerbate power density challenges [4][5]. - As chip sizes increase, the number of required I/O connections also rises, necessitating new packaging solutions like flip-chip packaging, which connects chips directly to substrate rather than through lead frames [6][7]. Group 3: Advanced Packaging Techniques - 3D stacking of chips using Through-Silicon Vias (TSV) allows for vertical signal transmission but complicates heat dissipation due to limited pathways for heat escape [9][11]. - The introduction of intermediary layers in 2.5D integration technology allows for more compact designs and improved signal routing, with the potential for multiple layers to enhance performance [13][14]. Group 4: Design and Verification Complexity - The design and verification process for five-layer interconnect systems is significantly more complex than in the past, requiring integrated efforts from chip and packaging design teams [17][21]. - Early-stage verification now includes structural material analysis, layout planning, and thermal simulations, expanding beyond traditional functional verification [20][21]. Group 5: Power Delivery and Signal Integrity - The increase in interconnect layers facilitates finer power delivery and signal integrity solutions, allowing voltage regulation to occur closer to the chip and improving overall performance [23][24]. - The integration of decoupling capacitors within the packaging can buffer voltage fluctuations, enhancing signal quality and performance [23][24]. Group 6: Conclusion on Industry Trends - The shift to a five-layer interconnect structure represents a gradual evolution rather than a revolutionary change, reflecting years of incremental improvements in semiconductor design [25][26]. - This complexity in interconnect design will influence future chip development decisions, emphasizing the importance of architecture-level considerations [26].