The Key Guarantee of Chip Yield - Unveiling the "Invisible Guardian" in Semiconductor Manufacturing

Introduction

In the precise world of chip manufacturing, a single micron-sized dust particle can cause the scrapping of a wafer worth millions. Behind this, there is an "invisible technology"—the cleaning process—that runs throughout the entire process, silently safeguarding the yield of each wafer.

I. Cleaning Process

Every step of chip manufacturing relies on cleaning. From silicon wafer polishing and photolithography etching to packaging and testing, the cleaning process accounts for over 33% of the total process, with a single chip undergoing over 200 cleaning steps!

Cleaning Process

Why is cleaning so important?

Removing fatal contaminants: Particles, metal ions, and organic impurities can directly cause short circuits or performance failures.

Ensuring process precision: Photolithography, etching, and other processes require a nanometer-level clean surface; otherwise, precision will be significantly reduced.

Adapting to advanced processes: For processes below 28nm, the sensitivity to impurities increases dramatically, and the difficulty of cleaning increases exponentially.

II. Wet Cleaning

Currently, wet cleaning dominates the market, achieving efficient cleaning through the precise mixing of chemical reagents and ultrapure water.

1) RCA General Cleaning Method: The RCA cleaning method uses solvents, acids, surfactants, and water to remove surface contaminants, organic matter, and metal ion contamination from the wafer surface through spraying, purification, oxidation, etching, and dissolution without damaging the wafer surface characteristics. After each use of chemicals, thorough cleaning in ultrapure water (UPW) is required.

RCA Cleaning Method Classification

2) Chemical Dilution Method: Based on the RCA cleaning method, using a dilution chemical method for the SC1 and SC2 mixtures can significantly reduce the consumption of chemicals and DI water. Furthermore, the H2O2 in the SC2 mixture can be completely removed. Diluting the APM SC2 mixture (1:1:50) effectively removes particles and hydrocarbons from the wafer surface. Strongly diluting the HPM mixture (1:1:60) and diluted HCI (1:100) are as effective as standard SC2 liquid in removing metals.

Another advantage of using diluted HCI solution is that particles do not precipitate at low HCI concentrations. Using the diluted RCA cleaning method can reduce the overall chemical consumption by 86%. Diluting SC1, SC2 solutions and HF, followed by megasonic agitation, can lower the operating temperature of the bath solution and optimize the time for various cleaning steps, thus leading to a longer bath solution life and reducing chemical consumption by 80-90%. Experiments have shown that using hot UPW instead of cold UPW can reduce UPW consumption by 75-80%. In addition, various diluted chemical liquids can significantly save rinse water due to low flow rate or cleaning time requirements.

III. Future Challenges

As chip processes move towards 3nm and 2nm, cleaning technology faces even higher demands:

Microscopic cleaning: Removing sub-nanometer contaminants requires the development of new reagents and ultra-precise equipment.

Process synergy: Deep coupling with etching, deposition, and other processes to achieve "zero-damage" cleaning.

Sustainable development: Reducing the consumption of chemicals and water resources to promote green manufacturing.

Conclusion

Although the cleaning process is "invisible," it is the lifeline of chip yield. [Company Name] will continue to cultivate cleaning technology innovation to provide high-reliability solutions for the global semiconductor industry, helping every chip break through its performance limits!

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[Company Name]—Leading the Innovation of Semiconductor Cleaning Technology

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