Monthly Archives: September 2020

Improving Wafer Manufacturing Processes with Automated Equipment

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Improving Wafer Manufacturing Processes with Automated EquipmentAutomated wafer fabrication equipment can improve semiconductor manufacturing facility performance, but all the associated process settings must be programmed properly. Before the manufacturing process can be implemented on a fully automated wet bench station, the settings, timing and other parameters have to be fine tuned. As circuit geometries and micro-structures become smaller and more tightly packed, the chemical concentrations, temperature levels and timed intervals affecting the etch rate become more and more critical. Fully automated equipment can precisely and reliably run a semiconductor manufacturing process once the correct variables are determined and programmed.

Manual Operation Can Determine the Settings for the Process Variables

Once wafer fabrication processes such as KOH etching are chosen, the process variables can be selected. Etching can be either isotropic or anisotropic and etching speed or precision can vary. Other factors may come into play as well. Initially it makes sense to run the new process on a manual station so that the process results for rough settings of basic variables such a concentrations, temperature and timing can be determined. These variables can then be adjusted to get an initial and acceptable process result.

Semi-Automatic Operation Can Fine Tune the Process

After determining the rough settings of the basic variables in manual operation, transferring to semi-automatic operation to optimize the process steps can save time. Those variables that will no longer change can be programmed into the semi-automatic software control while the others can be adjusted manually to get the best process result. In this way, as each process step is optimized, it can be programmed so that when optimization is complete, the process is ready to run on fully automated wafer processing equipment.

Fully Automated Operation Improves Semiconductor Manufacturing Facility Performance

Fully automated wet process stations for which the process has been optimized in manual and semi-automated operation can help improve overall production facility performance in the following ways:

  • Programmed settings ensure that the process is repeatable for different batches
  • Use of wet processing simulation software during optimization helps ensure accurate process parameters
  • Full automation eliminates human error
  • Precise dosages of chemicals and accurate timing results in fewer defective products
  • Throughput and wafer yields are increased

The programmed settings can be used again to get an identical result and they can be used for similar applications with minor adjustments. Instead of relying on operators to prepare etching baths, the fully automated station mixes the required chemicals quickly, safely and reliably, always the same way and without waste or spillage. The result is precise control over the process steps, fast execution without delays and high output quality.

Improved Output Relies on Optimized Software and Fully Automated Stations

Using an optimization strategy with manual and semi-automatic operation and running the optimized process on fully automated wafer fabrication equipment can lead to continuous improvement in semiconductor manufacturing operations. As new processes are brought online and optimized, they replace older versions that may not use chemicals as efficiently, may rely on some manual input or may not have the same precise and reliable execution as the fully automated stations. Tailor-made software working with fully automated wet process equipment can result in such continuous improvements.

With 40 years of experience in wet process technology and extensive in house expertise from manufacturing its own equipment, Modutek is ideally situated to supply fully automated equipment that improves semiconductor manufacturing output. The company has a complete line of standard and custom-built wet process equipment and the SolidWorks software used to calculate process parameters is programmed in house. Working closely with its customers, Modutek designs and builds its fully automated stations and programs the corresponding software to help them meet their goals for continuous improvement. Contact Modutek for a free quote or consultation on selecting equipment that supports your specific manufacturing process requirements.

How Specialized Wet Bench Equipment Improves the RCA Clean Process

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How Specialized Wet Bench Equipment Improves the RCA Clean ProcessThe RCA clean process removes contaminants from the surface of silicon wafers so that additional wet process semiconductor manufacturing steps can take place. The process consists of two steps, with the SC1 step removing organic compounds and the SC2 step dislodging any remaining metallic residues or particles. Specialized wet benches ensure that contaminant and particle removal is as complete as possible and the silicon wafers remain clean. To accomplish this, the equipment carefully rinses away contaminants and minimizes the handling of the wafers. Automation can be used to replicate process parameters reliably and consistently. Modutek can supply both standard and customized specialized equipment to carry out the RCA clean process.

RCA Clean SC1 Removes Most of the Wafer Surface Contamination

The SC1 cleaning step uses chemicals to dissolve impurities while leaving the underlying silicon surface unaffected. The wafers are placed in a solution containing equal parts of NH4OH (ammonium hydroxide) and H2O2 (hydrogen peroxide) in five parts of de-ionized water. The solution is heated to about 75 degrees centigrade and the wafers are left in the solution for ten to fifteen minutes. Organic residues are dissolved and particles are removed. A thin layer of silicon oxide forms on the wafer and there is some contamination with metallic ions and particles.

RCA Clean SC2 Removes Metallic Impurities

For SC2, the newly cleaned wafers are placed in a bath containing equal parts of hydrochloric acid and hydrogen peroxide in five parts of de-ionized water. The exact ratio may vary depending on the application. The bath is heated to about 75 degrees centigrade with the wafers soaking for about ten minutes. The solution specifically eliminates alkali residues, metal hydroxides and other metallic particles. The wafers are now completely clean and free of all types of particles.

Wafer Cleaning Equipment Has to Fulfill Specialized Functions

Specialized equipment is needed to carry out RCA clean process steps effectively. The required chemicals have to be delivered in the right quantities to the cleaning baths and then, when the chemicals are no longer needed, they have to be neutralized and disposed of safely. The concentration of the chemicals, the bath temperature and the timing are all important for being able to subsequently reproduce the desired cleaning performance. Contaminants and particles have to be rinsed away and filtered out. Key features of effective cleaning are a low particle count on the wafer surface and a resulting low rejection rate for fabricated wafers.

Modutek’s Wet Process Equipment Provides Specialized Features

Modutek’s wet benches and chemical stations support both of the RCA cleaning steps. Chemical delivery systems ensure that the right amounts of chemicals are supplied to the process safely and that waste chemicals are neutralized before disposal. The FM4910 material of construction keeps particle contamination low and is safe to use with the acid and base processes of RCA clean. All baths include a continuous flow de-ionized water chamber with chemical circulation and filtration to rinse away and remove contaminants. The SolidWorks flow simulation software lets operators calibrate dosages precisely and store settings for future use.

As well as fulfilling customer needs from its extensive line of wet process equipment, Modutek can build custom systems for specific applications. Customers who wish to incorporate drying, etching or stripping functions as well as RCA clean in their process lines can rely on Modutek to design and build exactly what they need.

With 40 years of experience in the wet process and technology sector and one of the leading semiconductor equipment manufacturers, Modutek has the expertise in house to provide specialized equipment for the RCA clean process and other semiconductor manufacturing applications. Customers can count on Modutek to help them find effective solutions and supply the corresponding equipment. Contact Modutek for a free quote or consultation to discuss your process equipment requirements.