How Megasonic Cleaning Reduces Costs and Improves Silicon Wafer Yields
Between process steps that etch silicon wafers and deposit circuit paths, semiconductor manufacturing relies on wafer cleaning to remove material from previous process steps and microscopic contaminating particles. As structures and circuits on wafers decrease in size, even the tiniest particles can interfere with etching and the creation of circuits and micro-structures. Such interference can […]
Improving Piranha Etch Process Results in Silicon Wafer Cleaning
Piranha etch is a popular process for silicon wafer cleaning, but it has to be tightly controlled to be effective. The mixture of about one part hydrogen peroxide and three parts sulfuric acid rapidly removes organic matter from silicon wafers. The etch process takes place in heated quartz tanks where both temperature and chemical concentration […]
Improvements to the SPM Process Provides Significant Results
Wet bench semiconductor manufacturing relies on the SPM wafer cleaning process to quickly strip photoresist and other residue from silicon wafers. Because the hydrogen peroxide in the sulfuric acid peroxide mixture is unstable, hydrogen peroxide continuously degrades into water and the degradation is accelerated if the mixture is heated to increase the strip rate. To […]
Why High Temperature Quartz Baths Are Required for Silicon Wafer Cleaning
Silicon wafers undergo many process steps during the manufacture of semiconductor components and cleaning the wafers properly is an important factor in successful fabrication. Process steps include etching and diffusion, both of which involve coating the wafer with masking material to guide the etching chemicals or diffusion targets. Once a step is completed, the masking […]
Improving Silicon Wafer Cleaning with the Piranha Etch Process
The Piranha etch process removes organic material from silicon wafers rapidly and completely. Semiconductor manufacturing involves the repeated etching and cleaning of the silicon wafers and the Piranha mixture is a favorite method for the resist strip of wafers to prepare them for further processing. Modutek can provide high temperature re-circulating and constant temperature quartz […]
Why Pre-Diffusion Cleans Are Important for Silicon Wafer Cleaning
Pre-diffusion cleans are carried out several times during the semiconductor manufacturing process, and each time the chemical residues and particles on the wafers have to be removed as completely as possible. If silicon wafers still have surface contamination when they are placed in the diffusion oven, diffusion may be uneven and the resulting semiconductor products […]
How Customized Equipment Has Improved the Silicon Wafer Cleaning Process
Different customized systems or custom components may improve silicon wafer cleaning processes because customers have special requirements or because the process characteristics are unusual. Suppliers taking on such projects must have extensive in-house experience and expertise together with a board line of silicon wafer cleaning equipment to provide custom solutions. When customization is required, effective […]
New SPM Process Provides 75% Improvement in Chemical Savings
Earlier this year Modutek started implementing its new SPM process with automatic adjustment of the sulfuric peroxide mix concentration and the company now has benchmark results from real process applications. Normally the SPM mixture deteriorates continuously as the hydrogen peroxide turns to water and dilutes the concentration. The SPM mixture has to be completely replaced […]
How Pre-Diffusion Cleans Are Used in the Wafer Cleaning Process
The silicon wafers processed in semiconductor manufacturing facilities and research centers are repeatedly cleaned in aggressive chemical cleaning baths used to remove surface contaminants from the wafers. The cleaning is important because surface impurities affect the diffusion of dopants in the diffusion ovens. Depending on the next diffusion step, wafers have to be completely clean […]
Changes to the SPM Process Improves Efficiency and Results
The sulfuric acid hydrogen peroxide mixture (SPM) process effectively strips and cleans wafers but suffers from instability due to the decomposition of the hydrogen peroxide. A heated bath improves performance but increases the rate at which hydrogen peroxide changes into water. Periodically spiking the mixture with extra hydrogen peroxide can restore the required concentration but […]