How the SPM Clean Process is Supported in a Wet Bench Process

Semiconductor manufacturing involves the use of many processing procedures, which include cleaning silicon wafers using wet bench technology.

The sulfuric peroxide mix (SPM) solution uses 3 parts sulfuric acid and 1 part of hydrogen peroxide at about 130 degrees Centigrade to remove any organic material and photoresist from silicon wafers fast and effectively. Process engineers using the SPM clean process in semiconductor fabrication need to ensure that the chemical ratio and temperature are maintained within the safety confines and that the wafers and the solution are safely contained in impervious baths.

Modutek's wet benches support the SPM process in their manual, semi-automatic and fully automatic versions. These wet bench stations are also available in a wide range of configurations, and the designs can be customized.

In quartz recirculating baths, the SPM solution has to be heated quickly in a bath that can tolerate high temperatures and will not react with the strong chemicals. Heating has to be controlled and even, because at high temperatures the hydrogen peroxide would disintegrate and the solution has to be spiked with more peroxide to maintain its concentration.

Modutek's quartz baths support all the requirements for the SPM process. These quartz baths have an operating temperature that range from 30 to 180 degrees centigrade and feature a standard heat up rate of 2 degrees centigrade a minute. The operating temperatures can be regulated to within plus or minus one 1 degree centigrade. The liquid level sensor feature is optional. The tanks are available in standard sizes and depths, but they can also be customized as well.

Modutek's wet bench stations and quartz baths are cost-effective, designed to reduce errors as well as to improve performance, leading to higher throughput and better output quality. For a free consultation or to get a quote, contact Modutek or email Modutek@modutek.com. For more details read the complete article titled “How the SPM Clean Process is Supported in a Wet Bench Process”.

How Megasonic Cleaning Technology Improves Silicon Wafer Yields

Silicon wafer cleaning is an essential and critical part of semiconductor manufacturing. Particles must be removed from the wafer substrate during processing without damaging the delicate microcircuit structures. This will result in defective semiconductor components or low-quality output.

In megasonic cleaning systems, a megasonic frequency generator creates high-frequency sound waves in a liquid via a transducer which is submerged in a cleaning tank. The sound waves are compression waves that appear either in high-frequency peaks or low-frequency troughs. The low-frequency troughs produce cavitation bubbles which break down in high-pressure peaks. These bubbles provide the cleaning action for removing contaminants that are on the surface of the wafer. Low ultrasonic frequencies (20 to 40 kHz) produce large, high-energy bubbles which clean more robust surfaces, while high ultrasonic frequencies produce smaller bubbles, ideal for cleaning delicate components.

The megasonic cleaning technology used in the process will effectively remove sub-micron particles and contaminants without damaging or altering the wafer's surface. Selecting the right frequencies and power levels is essential for effective cleaning results. Modutek incorporates the Kaijo Corporation high-frequency Megasonic Cleaning technology into its wet bench process equipment.

Kaijo's megasonic generators in Modutek’s wet benches operate at 950 kHz in the standard version. Other frequencies are also available for a variety of cleaning applications. Modutek has included Kaijo's megasonic cleaning system in both direct and indirect bath designs. Semiconductor facilities can use Modutek's wet benches which incorporate the use megasonic cleaning technology to effectively improve yields. Benefits of using the technology include faster cleaning time, higher cleaning effectiveness, and lower use of costly chemicals and their disposal.   

If you have questions about using Modutek’s wet bench stations which incorporate megasonic cleaning technology, call Modutek or email Modutek@modutek.com. For more details read the the full-length article entitled “How Megasonic Cleaning Technology Improves Silicon Wafer Yields.”