ElectroScrub3

The Solution For Contamination-Sensitive Cleaning Needs

• Increased Particle Removal Efficiency (PRE)
• 3x Faster than Typical SC-1 Processes
• Removes Particles without Mechanical Force, Undercut Etching or Elevated Temperatures
• Safe for most surfaces including Ti, TiN, and W
• Can Be Used in Single Wafer or Batch Type Equipment
• Effective at Many Stages of the Manufacturing Process
• High Perfomance and Cost Effective

ElectroScrub3 is a technologically advanced cleaning chemistry designed to meet the challenges of cleaning without damage. Intricate surface patterns present an increased degree of difficulty to the FEOL processes. ElectroScrub3 provides effective cleaning characteristics at ambient temperatures in static or filtered recirculated baths.

The current FEOL process SC-1(Standard Clean 1) or APM (Ammonia Peroxide Mixture) requires heated chemistry and the addition of megasonic energy to achieve acceptable cleaning results. Mechanical surface damage from high power megasonics and under cut etching from elevated chemistry temperatures are undesirable byproducts of this cleaning process.

SOLUTION MAKE UP

ElectroScrub3 diluted 1:30 with DI water cleans effectively at room temperature without causing mechanical damage and without etching the wafer surface .

ElectroScrub3 can be substituted for NH4OH in a SC-1 or APM process chemistry.

VARIETIES

ElectroScrub3 is an ammonia based product that works well with most Semiconductor cleaning applications. In addition it can be used to clean Ti, TiN and W surfaces.

Another variation of ElectroScrub3 is made on the basis of TMAH. This is recommended for use on Cu.

TYPICAL APPLICATIONS

Typical applications include Post STI etch cleaning in Post Gate Etching cleaning in Logic applications and Post STI etch clean, Post Gate Etch clean, Post Poly Wordline clean and Post Metal 1 Bitline clean in memory applications. For stacked DRAM memory, the post stacked cell clean is also popular.

APPLICATION DATA

ElectroScrub3 works by putting a strong negative charge on both the particle and the substrate surface. This creates a strong repulsion force removing the particle from the surface. DI water rinsing then carries the particle away from the vicinity of the wafer surface into the bulk liquid and down the drain. When the particles are separated from the surface they are moved away from the substrate and filtered out in the bath re-circulation system.

A comparison in particle removal efficiency for a 1min immersion in ElectroScrub3 at room temperature compared to a similar immersion in NH 4 OH water with roughly the same pH is shown in the following table:

A comparison for longer immersion times (10min) is shown in the following table:

NOTE: All of the above experiments were done at ambient temp with static baths.

The challenge particles were wet deposited and dried on SiO 2 particles with a size of 200nm-300nm. Longer exposures improve the particle removal efficiency.

ElectroScrub3 is very popular for those applications where strong mechanical force cannot be used to remove particles due to the fragility of the exposed structures.

EQUIPMENT RECOMMENDATION

ElectroScrub3 is extremely effective in both Single Wafer or in Batch Type equipment. Single Wafer equipment is typically dispense-spin type. Single Wafer equipment can also be the Confined Chemical type or the Immersion Type. Batch Type equipment is typically either bath (or tank/immersion) type or spray type.

MATERIALS OF CONSTRUCTION : PFA recommended for supply lines. Batch Tank material PFA or quartz glass. Single Wafer Bowl material PVDF or Polyethylene/Polypropylene. Drain lines PFA, PVDF, Polyethylene, Polypropylene, PVC.

NOTE: Most single wafer tools do not adequately rinse the surface of the wafer.

ElectroScrub3 removes particles from the wafer surface by electrostatic repulsion. However, rinsing is required to carry the particles from the liquid phase close to the wafer (10-100nm) into the bulk liquid and eventually down to the drain.

OPERATIONAL DATA

SOLUTION MAINTENANCE

Regular renewal of the solution or single pass use is recommended. Solution renewal is based on PRE, solution contamination, etc.

METHOD OF CONCENTRATION MONITORING

Conductivity, Refractive Index, Spectroscopic methods may all be used to monitor the ElectroScrub3 solution. An initial signature figure needs to be obtained and this can be used to monitor the state of the solution.

PROPERTIES

Flashpoint: not flammable

Auto-Ignition Temperature: not flammable

Appearance: yellow liquid

Odor: ammonia odor

Boiling Point: >50° C

Melting Point: <-5° C

Specific Gravity: 1.0 g/cm3

Solubility in H 2 O: completely soluble

pH: 9 - 11 (after dilution with H2O 1:30 )

Shelf Life: 6 months

SAFETY

For safety information, please consult the Material Safety Data Sheet for this product.

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