The Complete Guide to Laser Marking

Laser marking plays a crucial role in the silicon wafer manufacturing process. An optical laser machine creates a permanent mark on semiconductor packages by using a beam of concentrated light.

It’s not just a word, and it stands for “Light Amplification by Stimulated Emission of Radiation.” A laser generates focused and directed light particles precisely by stimulating an atom. By using a laser marking machine, this can be done specifically.

Laser marking allows wafers to be tracked throughout the production process. Automatic reading of the laser marking is therefore necessary. Furthermore, there must be attention to detail, as the marking cannot adversely affect the underlying processes, and no damage to the wafer can occur. Maintaining it perfectly is paramount.

As part of our entire process, Wafer World offers laser marking services for silicon wafers.

How does a silicon wafer work?

What is laser marking? Laser marking is a technique for identifying silicon wafers. Like semiconductors, wafers can be found in almost all kinds of electronic devices. The surface appears to be flat, circular, and mirrored.

As silicon wafers have no impurities, they require exceptional care during laser marking to ensure they remain faultless.

Laser Beam Characteristics

Precision is essential in fabricating silicon wafers, so lasers are the perfect tool when accurate measurements are needed. In addition to these characteristics, laser beams used in marking have the following attributes:

  • The same color is used in monochromatic patterns
  • The spatial and temporal phases of light waves are in phase

Annealing with a laser

A laser beam is used in annealing to heat surfaces exceptionally efficiently. Oxygen is diffused below the surface after the surface is heated (oxidation). When everything is cooled, you can see that the color changes.

An annealed product can produce a variety of colors, including yellow, red, and green. As the temperature changes during marking, these colors can change as well. It depends on three variables whether the temperature goes up or down:

  • The pulse’s intensity
  • Optical speed
  • Passes between each line

Characters can be rendered as small as a millimeter tall with these lasers. Using lasers to mark silicon-based wafers, an annealing process is popular due to its excellent results.

A Brief Overview of Laser Marking

To mark silicon wafers, computers must be used. A marking document contains a map of the wafer at this point in the process. Information about the different parameters, functions, etc., is collected here. A preview view is available on the other side of the screen, showing how the data will be translated into silicon.

In the laser marking machine, the wafer will be placed after everything is set up correctly. The wafer is taken by a mechanical hand and brought to the marking position. Human interaction is not necessary throughout the entire process, which will be completely automated.

The laser is then aimed at the wafer surface when the machine has found its target location. After this is complete, the project will be transported to the receiving box to be removed.

Laser marking offers several advantages.

High-Precision

Due to its precision, laser marking is an excellent choice for wafer manufacturing. Its superior technology ensures that the tiniest details will always be perfectly detailed and accurate. Computers can read silicon wafer markings that are as small as a millimeter for easy tracking.

Super-fast

Besides being extremely precise, laser marking is also high-speed. From placement to marking to completion, entire silicon wafer stacks can be observed in minutes. Despite its slower speed, laser annealing leaves an excellent finish without leaving anything behind.

Applied only to the surface

No material is removed from the surface of a silicon wafer during laser marking. The result is only a change in color underneath the surface. Perfect conditions are maintained at all times.

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