Ceramic Particles for Advanced Packaging: Powering the Polyimide Application Frontier

3.5 minute read

As the semiconductor industry strives to keep up with Moore’s Law, innovations in advanced packaging are playing a pivotal role in delivering the next generation of high- performance, energy-efficient, and compact devices. At the heart of this transformation lies a key enabler: chemical mechanical planarization (CMP) using engineered ceramic solutions - a core area of expertise within Saint-Gobain’s Surface Conditioning business.

This blog post explores the importance of advanced packaging, the critical role of planarization, and the emerging relevance of polyimide applications. It focuses on how CMP slurries built from advanced ceramic materials are helping meet the rigorous demands of modern semiconductor manufacturing.

Why Advanced Packaging Matters

Advanced packaging allows multiple chips or components to be integrated into a single package, offering higher functionality in a smaller footprint. As continued transistor down-scaling becomes more challenging, advanced packaging becomes the go-to solution for improving performance.

These methods, such as 2.5D packaging, 3D integration, fan-out wafer-level packaging, and system-in-package (SiP), enable faster signal transmission, lower power consumption, and reduced latency. Advanced Packaging is especially critical for cutting-edge applications like artificial intelligence, machine learning, automotive electronics, and 5G communications, where processing vast amounts of data in real-time is essential (Semiconductor Engineering, 2023).

Example of 2.5D (left) and 3D (right) semiconductor packaging architectures.

How Saint Gobain’s Ceramic CMP Particles Make the Difference

At Saint-Gobain, our engineered alumina and zirconia solutions are designed specifically to meet the demanding requirements of planarization in advanced packaging. Our particles offer a unique advantage: while they possess high hardness, their controlled morphology enables an efficient material removal rate (MRR); especially when applied to challenging materials like polyimide.

Unlike generic abrasives, Saint-Gobain’s particles are specially synthesized allowing for precise bulk removal while minimizing surface defects. This characteristic makes it exceptionally well-suited for polyimide and silicon planarization, where maintaining surface integrity is as important as achieving topography control.

Our alumina- and zirconia-based CMP materials are formulated to:

• Effectively remove bulk material, such as polyimide dielectric layers.
• Deliver controlled surface conditioning that supports downstream packaging steps.
• Maintain stable performance across varying topographies, especially in 2.5D and 3D packaging scenarios.

Saint-Gobain’s Surface Conditioning business has seen notable success in polyimide applications, where high removal performance and controlled finish quality are critical to next-gen chip stacking and packaging workflows.

By optimizing the polishing interaction between substrate and slurry, Saint-Gobain helps ensure a high-quality finish while minimizing risk and improving throughput.

The Critical Role of Planarization in Packaging

A crucial aspect of advanced packaging is ensuring that the surfaces between advanced packaging layers must be planarized making them smooth, defect-free, and ready for further processing.

Planarization ensures that no unwanted topography or roughness interferes with the alignment of subsequent layers. If not addressed, these irregularities can lead to bonding failures, misalignment, or compromised electrical performance, all critical risks in today’s compact chip architectures.

The chemical-mechanical planarization (CMP) process begins with bulk material removal, using abrasive particles to remove polyimide and level the surface. This is followed by a finishing stage that delivers a smooth, uniform topography, ready for hybrid bonding or further layer deposition (Nimbalkar et al., 2023).

Understanding Polyimide Applications in Packaging

Polyimide, a high-performance polymer, is frequently used as an interlayer dielectric in advanced packaging due to its excellent thermal stability, moisture resistance, and low process cost (Nature, 2022). It is particularly common in back-end-of-line (BEOL) manufacturing processes.

In multi-chip modules and stacked die configurations, polyimide acts as a spacer and protective layer that must be uniformly planarized to facilitate vertical integration. Uneven polyimide layers can lead to voids, stress points, and poor electrical connections during die stacking or interposer bonding.

Achieving the correct surface finish without over-polishing or damaging underlying layers is a delicate balancing act, enabled by ceramic-based CMP slurries (GitHub CoWoS Guide).

CMP with Saint-Gobain

From bulk polyimide removal to fine polishing for hybrid bonding, ceramic particles are enabling the next leap in chip integration. At Saint-Gobain Surface Conditioning, we combine materials expertise with a commitment to innovation, ensuring our solutions keep pace with the most advanced packaging demands.