Pulse Plating

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Sample forward & reverse waveform from Pro Series Power Supply

In the typical electroplating process, direct current (DC) is supplied to the plating bath as straight DC current. In pulse plating, the DC power arrives in the bath in a series of short pulses. These pulse cycles can be regulated at predetermined rates to over 10,000 times per second. Precise changes in the regulation of these cycles provide different results to the plated deposits, depending on the metal being plated. Typical advantages of pulse plating include better distribution, lower porosity, higher density, greater throwing power, improved hardness and less metal usage.

Dynatronix offers two types of pulse cycles: High Frequency Pulse (HFP) and Low Frequency Pulse (LFP). The frequency range of our high frequency pulse runs from 0-5000 Hz. High frequency pulse is extremely versatile, allowing for pulse timing settings ranging from 0.1 milliseconds to 99.99 seconds. It is often associated with precious metals plating, nickel electroforming and copper plating of semiconductor wafers and printed circuits.

The LFP at Dynatronix has a frequency range of 0-200 Hz. Pulse timing settings range from an “on” time of 4-9999 milliseconds to an “off” time of 0-9999 milliseconds. While not as versatile as high frequency pulse, it has the advantage of a significantly lower cost. It is primarily used in applications such as nickel plating and other non-precious metals.

Advantages of Pulse Plating

Metallurgical

  • Denser deposit
  • Lower porosity
  • Finer grain deposit
  • Higher tensile strength
  • Higher elongation
  • Reduced stress
  • Reduced hydrogen embrittlement

Physical

  • Improved adhesion of deposit
  • Increased throwing power
  • More uniform thickness
  • Fills sub-micron trenches
  • Reduced stress on photo resists
  • Better control of alloy composition
  • Better color control

Electrical

  • Higher conductivity
  • Lower contact resistance
  • Better bondability

General

  • Reduced process limitations
  • More flexibility of metal content in bath
  • Reduction/elimination of additives
  • Reduced process (plating) time

Common Applications and the Benefits of Pulse

Soft Gold Plating
Finer grain deposit, denser deposit, reduced metal consumption, improved uniformity, reduced plating time

Nickel Plating/Electroforming
Finer grain deposit, increased hardness, higher tensile strength, more uniform thickness control

Hard Gold Plating
Finer grain deposit, lower porosity, decreased cracking, more uniform thickness control

Nickel Diamond Plating
Increased hardness, higher tensile strength, more uniform thickness control

Platinum Plating
Finer grain deposit, lower porosity, decreased cracking, more uniform thickness control

Chrome Plating
Denser deposit, increased hardness, greater wear resistance, reduced plating time

Rhodium Plating
Finer grain deposit, lower porosity, decreased cracking, more uniform thickness control

Nickel/Iron Plating
Better control of alloy composition, better thickness distribution

Tin Plating
Finer grain deposit, reduced surface roughness

Electropolishing
Smoother surfaces, reduced streaking

Copper Plating
Fills submicron trenches, fewer voids, more uniform thickness control

Anodizing
Reduced process time, greater thickness