Advanced Packaging
Beyond Moore's Law — 2.5D interposers, 3D die stacking, fan-out wafer-level packaging, and TSV substrates. Enabling the chiplet revolution and heterogeneous integration at scale.
Overview
Advanced packaging has emerged as the third dimension of semiconductor scaling — complementing traditional transistor density improvements (Moore's Law) with architectural innovations that dramatically increase functional density, interconnect bandwidth, and energy efficiency. As the cost and complexity of migrating to each new CMOS node escalate, advanced packaging enables system-level performance scaling through heterogeneous integration — combining dies from different process technologies (logic, memory, analog, RF, photonics) into a single integrated package.
The market reflects this strategic importance: advanced packaging revenue exceeded $40 billion in 2024 and is projected to grow at >10% CAGR through 2030, driven by AI accelerator demand (GPU + HBM on silicon interposer), chiplet adoption for next-gen CPUs, and 5G/mmWave Antenna-in-Package modules.
Packaging Technologies
2.5D Interposer — Si Interposer with TSVs
A silicon interposer — essentially a passive silicon substrate with through-silicon vias (TSVs) and multi-layer RDL — sits between the active dies (logic, HBM, I/O chiplets) and the organic package substrate. This provides ultra-high-density die-to-die interconnects (L/S down to 0.4/0.4μm) that are impossible to achieve with traditional flip-chip substrate routing. The dominant architecture for AI/ML GPU + HBM integration (NVIDIA, AMD, Intel).
3D-IC Stacking — Die-to-Die & Die-to-Wafer
Active dies are stacked vertically and interconnected through micro-bumps or hybrid bonding (Cu-Cu direct bonding). Enables massive bandwidth density (TB/s/mm) with minimal interconnect power. Essential for HBM (8–12 die stacks), 3D NAND (>200 layers), and emerging compute-on-memory architectures for AI inference at the edge.
Fan-Out Wafer-Level Packaging (FOWLP)
Individual dies are embedded in a molded epoxy wafer and interconnected via RDL traces that "fan out" beyond the die edges — eliminating the need for an organic substrate. Provides thinner profile, better thermal performance, and lower cost than flip-chip BGA. Dominant in smartphone application processors and PMICs.
RDL-First / Chip-Last Fan-Out
RDL layers are fabricated on a temporary carrier before die placement and molding. This enables finer RDL line/space (down to 1/1μm) compared to chip-first approaches, as the RDL is fabricated on a perfectly flat surface without die topography. Ideal for high-density multi-chip modules for RF and mmWave applications.
Embedded Die in Substrate ( laminate )
Active and passive dies are embedded within the layers of an organic laminate substrate — rather than mounted on top — reducing the z-height and shortening the electrical path between die and substrate routing. Used in ultra-thin packages for wearables, IoT modules, and automotive radar MMICs.
Glass Core Substrate & Interposer
Glass substrates with through-glass vias (TGVs) are emerging as an alternative to silicon interposers for 2.5D packaging. Glass offers: near-zero dielectric loss (ideal for mmWave RF), adjustable CTE (matched to Si or PCB), large panel format (lower cost vs 300mm Si), and transparency (enables optical inspection). Intel has announced glass core substrates for next-gen data center products.
Available Process Services
Multi-layer Cu redistribution layers with polyimide or BCB dielectric. Fine-line (L/S down to 1/1μm) Cu damascene or semi-additive plating. Integrated passive devices (IPD) on RDL layers — inductors, capacitors, resistors for impedance matching.
Deep reactive ion etching (DRIE) of high-aspect-ratio TSVs. LPCVD SiO₂ liner for sidewall isolation. PVD Ti/Cu barrier/seed, followed by Cu electroplating fill (bottom-up super-fill). CMP for Cu reveal. Via-middle and via-last process flows.
Wafer support systems for thin-wafer handling during backside processing. Thermoplastic and laser-release temporary bonding materials. Carrier wafers (Si or glass) for warpage control on thinned wafers (< 50μm).
Direct Cu-to-Cu bonding with simultaneous dielectric bonding (SiO₂-SiON). Sub-micron alignment precision. Room-temperature bonding followed by low-temperature anneal (200–400°C). Enables face-to-face and face-to-back 3D stacking.
Fine-pitch micro-bumps (10–55μm pitch) for die-to-die and die-to-wafer stacking. Cu pillar bumps with SnAg solder cap. Low-volume prototyping and pilot production volumes supported.
Stealth dicing (laser), blade dicing, and plasma dicing options. Optimized for thin wafers, low-k dielectric stacks, and glass substrates. Post-dicing sidewall inspection and cleanliness verification.
Key Application Areas
2.5D silicon interposer integration of GPU/TPU + HBM stacks with >1 TB/s memory bandwidth. TSV-based vertical power delivery for reduced IR drop.
Disaggregated SoC designs where compute, I/O, memory, and analog chiplets are integrated on a common interposer. Enables heterogeneous process node optimization, improved yield, and faster time-to-market.
Integrated antenna arrays, beamforming ICs, and up/down-converters in a single package using FOWLP or organic substrates. 24–81 GHz for 5G FR2 and automotive radar.
Multi-die fan-out or laminate integration of PA, LNA, switch, and filter dies with integrated passive matching networks — reducing module footprint by 40–60% vs discrete PCB assembly.
Wafer-level hermetic packaging with TSV electrical feedthroughs for inertial sensors, pressure sensors, microphones, and bio-MEMS devices. Anodic, eutectic, or glass-frit bonding seal rings.
High-temperature, high-vibration packaging for under-hood electronics. SiC power module packaging with AlN DBC substrates and Cu wire bonding or Cu clip interconnects for EV power trains.
RDL Design Rules & Capabilities
| Parameter | Standard RDL | Fine-Line RDL | Ultra-Fine RDL |
|---|---|---|---|
| Minimum L/S | 5/5μm | 2/2μm | 0.4/0.4μm |
| Cu Thickness | 5–8μm | 3–5μm | 1–3μm |
| Via Diameter | 20–30μm | 10–15μm | 5–10μm |
| Dielectric | Polyimide (PID) | Polyimide or BCB | SiO₂ (CVD) |
| Dielectric Constant (k) | 3.0–3.5 | 2.6–3.0 | 3.9 (SiO₂) |
| Number of Layers | 1–3 | 2–5 | 2–8 |
| Cu Deposition Method | Semi-additive (SAP) | SAP or Damascene | Cu Damascene |
| Planarization | None or CMP | CMP | CMP (per layer) |
Substrate Selection for Packaging
Substrate choice is a critical decision in advanced packaging design: silicon interposers offer the finest RDL pitch (0.4μm L/S) and established TSV process maturity — ideal for HBM integration — but are limited to 300mm wafer size and have higher cost. Glass interposers provide superior RF performance (low dielectric loss), tunable CTE, and panel-format economics (up to 510×515mm) — emerging as the preferred choice for mmWave and high-frequency packaging. Organic laminates (ABF, BT, coreless) remain the cost-effective solution for mainstream flip-chip and multi-chip module packaging with L/S > 5μm. Our engineering team can guide your substrate selection based on your specific electrical, thermal, mechanical, and cost requirements.
Quality & Metrology
Advanced packaging process control demands specialized metrology: confocal microscopy and AFM for RDL CD and surface roughness measurement, X-ray CT for TSV void detection and fill quality verification, CSAM (C-SAM) for bond interface inspection and delamination detection, and four-point probe for RDL sheet resistance uniformity. Every lot includes comprehensive process data with Certificates of Conformance.
Designing Your Advanced Package?
Tell us about your architecture — interposer type, RDL requirements, TSV specs, bump pitch, and volume — our packaging engineering team will provide a comprehensive technical proposal and quotation within 24 hours.