However, behind “thinner is better” lies immense technical challenges. Wafer thickness is reduced from an original 700~800 µm to 70~80 µm, and even further down to below 20 µm. This transformation makes wafers as fragile as paper, where any slight mechanical stress, surface unevenness, or micro-crack can lead to breakage and scrap. Against this backdrop, the concept of “thinness” conceals an extremely precise field of engineering, which is the core we will explore today.
However, behind “thinner is better” lies immense technical challenges. Wafer thickness is reduced from an original 700~800 µm to 70~80 µm, and even further down to below 20 µm. This transformation makes wafers as fragile as paper, where any slight mechanical stress, surface unevenness, or micro-crack can lead to breakage and scrap. Against this backdrop, the concept of “thinness” conceals an extremely precise field of engineering, which is the core we will explore today.
Table of Contents
Ultra-Flat Wafers: Why Are They the “Invisible Champion” of Semiconductor Processes?
The importance of wafer surface flatness is often overlooked by the general public, yet it is an indispensable “invisible champion” in semiconductor manufacturing. In processes such as photolithography, thin-film deposition, and etching, even nanometer-level unevenness on the surface can lead to photolithography focusing errors, non-uniform film thickness, and uncontrolled etching depth, ultimately affecting the resolution and precision of circuit patterns.
Imagine building a skyscraper on an uneven foundation; even with the best building materials, it would be difficult to construct a stable structure. Similarly, wafer flatness directly determines the stacking quality of upper-layer circuits and the chip’s ultimate performance and yield. In advanced processes like FinFET or GAA architectures, nanometer-level differences can become fatal risks, which is precisely why planarization technology is increasingly vital.
Grinding and Polishing: Core Processes for Wafer Thinning and Ultra-Planarization
Backside Grinding
In semiconductor manufacturing, wafer thinning is not merely for saving material costs but is a crucial step for achieving advanced packaging and thermal management requirements. Wafer backside grinding technology is primarily applied in the latter stages of the process, especially after the front-side circuitry is completed and before packaging.
The original thickness of wafers is typically 700~800 µm. Through Coarse Grinding, most material is quickly removed, followed by Fine Grinding to achieve precise thickness and better surface quality. Typical process target thicknesses are 70~80 µm, and under demands for high-density stacking and ultra-thin packaging, it can be further reduced to 20~30 µm, supporting packaging technologies such as 3D ICs, MCP (Multi-Chip Package), and Heterogeneous Integration.
Back grinding requires exceptional attention to mechanical stress control and thermal effect management. To prevent wafer warping or breakage, a highly adhesive, cushioning protective tape is usually applied first and secured to the grinding platen, ensuring the circuit side remains undamaged. Furthermore, to minimize the risk of dicing thin wafers, the Dice Before Grinding (DBG) process flow can be adopted, where the wafer backside is marked and diced before grinding, allowing individual die to be less prone to breakage after thinning.
Honway’s grinding consumable designs consider these microstructural challenges, utilizing CMP-specific diamond grinding fluids with uniform particle size and controllable wear, combined with highly wear-resistant grinding pads, to achieve high-efficiency material removal while preserving wafer integrity and surface homogeneity. This technology is also applicable to hard and brittle materials such as SiC, GaN, and sapphire for advanced power component substrates.
Chemical Mechanical Planarization (CMP)
Chemical Mechanical Planarization (CMP) is an extremely critical “interlayer technology” in semiconductor manufacturing. It provides necessary surface conditioning after each thin film deposition or etching, ensuring the precision of subsequent processes and structural uniformity.
The core of CMP technology lies in simultaneously utilizing mechanical grinding force and chemical corrosive reactions to selectively remove protrusions on the wafer surface, achieving nanometer-level flatness (typically Ra < 1 nm, and can even reach sub-nm levels). Its key materials are:
- Polishing Slurry: Contains nano-sized abrasives, such as diamond, aluminum oxide, silicon dioxide, cerium oxide, etc., along with specific chemical additives, used for selective etching of the target material.
- Polishing Pad: A highly elastic polymer structure that provides grinding pressure and uniform fluid distribution.
CMP is widely applied in the following semiconductor process stages:
- Planarization after STI (Shallow Trench Isolation) filling: Eliminating height differences between the filled oxide layer and the silicon substrate.
- Metal layer (e.g., Cu, W) planarization: Ensuring uniform thickness of metal interconnect layers to avoid abnormal resistance.
Multi-Layer Interconnect (MLI) stacking: Each layer needs to be planarized with CMP after deposition; otherwise, stacking layers can lead to misalignment or short circuits.
Honway offers various CMP polishing liquid and polishing pad combinations that can provide optimal matching solutions based on different materials, such as Low-K dielectric layers, TaN barrier layers, copper, silicon dioxide, and varying selectivity requirements. Our nano-scale dispersion technology and stabilized formulations can effectively prevent polishing liquid agglomeration and scratch formation, achieving stable removal rates (RR) and reducing defectivity.
The “Thin” Challenge and Innovative Solutions from Grinding & Polishing Consumables
In the pursuit of ultimate “thinness” and “flatness,” traditional consumables can no longer meet the demands of modern processes. The Honway team combines materials science with process understanding to develop a series of innovative grinding and polishing consumables specifically designed to solve advanced process pain points.
- Stress Control for Ultra-Thin Wafers: Honway’s grinding liquids offer a gentle, uniform grinding action, paired with highly elastic polishing pad structures, effectively dispersing stress and reducing the risk of warping and micro-cracks. This protects ultra-thin wafers, maintaining their integrity throughout the process.
- Damage-Free Surface Grinding: Utilizing high-purity diamond micro-particles (particle size ≤ 50 nm) and special dispersion technology, our polishing liquids can effectively remove material while preventing scratches and sub-surface defects, making them ideal for high-end power components and high-frequency communication chips.
- Precise Removal Rate Control: The synergistic design of grinding liquids and polishing pads achieves extremely high material removal uniformity and rate control capabilities. Even for ultra-thin wafers below 20 µm, precise target thickness and flatness can be achieved.
Ultimate Cleanliness: All consumables feature low-residue, anti-contamination formulations, enabling particle-free and chemical-free polished surfaces that meet the most stringent process cleanliness standards.
How Honway Consumables Achieve Superior Thinning and Planarization
In high-spec semiconductor processes, our consumables successfully meet higher cleanliness standards and achieve greater operational reliability:
- Diamond Grinding Liquid: Honway’s diamond polishing liquid, specifically designed for high-hardness materials like SiC and GaN, achieves extremely low sub-surface damage during the back grinding stage, providing assurance for heat dissipation and reliability of high-power components.
- CMP Solutions: By combining Honway’s five-layer high-performance polishing pads with cerium oxide polishing liquid, we can reduce wafer surface roughness to Ra ≤ 10 nm and control TTV (Total Thickness Variation) within industry-leading standards, assisting in stable mass production of semiconductor processes.
- Precise Material Matching: Honway offers a variety of polishing liquid combinations, including aluminum oxide, silicon dioxide, cerium oxide, and diamond, that can be customized for different materials and process requirements, improving production efficiency and yield.
- Wafer Grinding Wheels: Our wafer surface grinding wheels are suitable for various wafer materials, featuring a stable high material removal rate, effectively shortening processing time and improving production efficiency. Their excellent wear control design ensures longer grinding wheel life and maintains low grinding resistance during the grinding process, reducing equipment load and protecting workpieces, ensuring stable processing quality. Particularly suitable for planarization and back grinding of silicon wafers.
- Silicon Wafer Chamfering Wheels: Specifically designed for chamfering and grinding semiconductor material substrates, these wheels employ high-precision finishing technology and feature a uniform, fine abrasive grain layer structure. After dressing, they achieve a low defect rate and excellent processing accuracy. The product line covers outer periphery and groove processing and offers various styles such as single-groove, multi-groove, and rough/fine mixed processing, meeting diverse process needs.
Conclusion
In today’s semiconductor processes, which are constantly pushing limits, the successful stacking of each chip layer and the precise formation of every circuit are built upon a thin and flat wafer. Honway deeply understands the importance of this “thin” science, dedicating itself to researching and developing consumable solutions that can meet future challenges, assisting the industry in creating smaller, faster, and stronger semiconductor products.
Let us use technology to grind the most solid foundation for a flat and smooth path ahead.
Act now, and let’s together open a new chapter in semiconductor precision manufacturing!
- Free Consultation and Project Evaluation: Our Honway diamond industrial consumable experts provide product consultation and professional evaluation tailored to your specific process needs, working together to find the optimal grinding and polishing solution.
- Customized Solution Design: Whether you are facing challenges with silicon wafers or compound semiconductors (SiC, GaN, GaAs), we can customize the most suitable semiconductor grinding and polishing solutions for your needs.
- Advanced Materials and Performance Verification: We offer industry-leading Honway diamond polishing liquids, diamond disks, precision grinding wheels, and other consumables. We can also assist you with process implementation and performance verification to ensure your products achieve the expected high yield and excellent performance.
- Honway possesses stable supply capabilities, quality assurance, after-sales service, and customized support, ensuring the most consistent product quality for you.
Don’t let processing challenges limit your innovation! Contact us now, and let Honway’s diamond industrial consumables be your key to success!
More Information on Honway Diamond Grinding and Polishing Consumables:
To learn more about how Honway can bring breakthrough benefits to your semiconductor processes, please click the links below to explore our full range of diamond grinding and polishing consumables and technical details:
- Honway Nanodiamond Polishing Liquid Series
- Honway Precision Wafer Grinding and Polishing Pads
- Honway Grinding Wheels for Wafer Surface Grinding
- Honway Chamfering and Grinding Wheels for Silicon Wafers
You can also directly “contact our Honway expert team,” and we will provide the most professional customized consultation and solutions.
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