Lam Research’s wet clean optimization helps chipmakers improve device performance

Preventive Maintenance

Calling it “wet” is actually “dry” and it sounds like a riddle, but for plasma process equipment the answer is “wet cleaning”, an important preventive maintenance method.

The term "wet cleaning" comes from the industry's early preventive maintenance methods, which involved disassembling the reaction chamber and immersing the quartz parts in acid water to rinse, then drying and reassembling. Today, for equipment that requires high-precision maintenance, the only commonly used "wet" substance is a lint-free cloth moistened with deionized water, but the traditional term "wet cleaning" has been used to this day. So the maintenance method is called "wet", but it is actually "dry".

The goal of preventive maintenance is to keep the equipment up and running and minimize any unplanned downtime, which can seriously disrupt production, lead to high costs and lost production. Just like a car, regular changes in the engine oil are key to maximizing the life and performance of the car. During the process of etching thousands of wafers, polymers of the removed material will accumulate on the surfaces of the plasma chamber.

We need to deal with such aggregates because they can become a source of contamination and because they can change the inductance or conductance in the chamber, which can affect the plasma process. Dealing with aggregates mainly relies on a mature plasma cleaning cycle, but sometimes it also requires regular preventive maintenance of the chamber.

The number of steps and precision requirements for this preventive maintenance have increased significantly. In 2000, the entire maintenance process only included about 35 steps, but now the number of steps has exceeded 150, and the precision requirements are much higher. Such a complicated maintenance process and high precision requirements result in a maintenance failure rate of up to 30%, which not only means production losses, but also causes the loss of spare parts and test wafers, and the resulting cost increases.

Wet Cleaning Optimization

To solve the above problems, Lam Research launched a service called "Wet Cleaning Optimization" (WCO) to eliminate human differences and improve the success rate of preventive maintenance. Today, WCO has been applied to a large number of etching and deposition chambers around the world, helping multiple customers solve problems such as improving yields and significantly reducing waste.

As a total solution, WCO includes professional equipment, localized multimedia step-by-step instructions, data analysis and expert support (to diagnose maintenance issues and drive continuous improvement).

Professional equipment

Using the right equipment can significantly improve productivity and efficiency while protecting personnel safety. WCO service packages ensure that customers have access to standard and custom equipment when and where they need it.

Multimedia step-by-step instructions

One of the biggest challenges preventive maintenance teams often face is the replacement of maintenance personnel (turnover rates can be as high as 100% in 18 months). In this case, step-by-step procedure instructions and easy-to-reference operating documents are very important.

Data analysis

This is a key component of WCO and its role is to transform wet cleaning data into actionable information. A key to driving continuous improvement is to identify the areas that need the most improvement through high-quality analysis and to measure and quantify those improvements.

Expert Support

Professional engineers drive accountability, investigate issues, and drive systemic improvements.

Application Scenario

We will help you better understand the role of WCO through the introduction of the following application scenarios.

Chipmaker A was experiencing unpredictable performance issues when using wet cleaning for its plasma etching equipment, which was affecting equipment availability. The fab manager understood that the cause of the problem was high employee turnover, but he was unable to improve the situation through internal training or other actions. After introducing Lam Research's WCO, localized step-by-step operation videos helped new employees quickly understand the situation, and soon achieved stable and high performance for wet cleaning. The time spent on wet cleaning and unplanned equipment downtime were reduced, and the equipment's uptime and yield were improved as a result.

Chipmaker B is using a new type of chamber to ramp up yield and hopes to achieve high productivity as soon as possible. By introducing the best practices provided by WCO, B's staff quickly mastered the essentials of operation, the difference in maintenance time was reduced, and the new chamber quickly achieved sustained and stable normal operation.

Summarize

WCO is a methodology that helps customers successfully perform preventive maintenance on their own. The holistic approach combines Lam’s proprietary software, data analytics, and certified cleaning procedures (with video instructions). WCO is also part of Lam’s Equipment Intelligence®, a comprehensive productivity solution based on Lam’s equipment experience and data.