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Types of Laser Dicing Processes for Semiconductor Wafers

There are several types of dicing processes used for semiconductor wafers, including Plasma dicing, Scribe dictating, Step dicing, and Stealth Dicing. Read on to learn about each type and which one is best for your needs. If you are not familiar with the different processes, read on to discover what they are and why they are important. Then, use the information in this article to choose the best one for your needs.

Plasma dicing

A method and apparatus for plasma dicing semiconductor wafers are disclosed. The method begins with the application of a patterned mask to the integrated circuit portions of the wafer. The mask is deposited to a thickness of four to five microns, thereby exposing the streets between the dice. A layer of adhesive material is then applied to the carrier wafer, which is then adhered to the wafer to be diced.

Once the adhesive film is applied, the wafer is placed on a frame. It is essential to maintain the shape and dimensions of the wafer, while ensuring that the chipping process doesn’t cause an air bubble. While an air bubble may pose only a minimal risk to the wafer, it can cause an arc and eventually burn a hole in the wafer. This type of damage is particularly troublesome when the wafer is made from crystalline material.

Scribe dicing

The benefits of scribe laser dicing of semiconductor wafer are numerous. These include high throughput, low cost, process tolerance, high yield, and uniformity. Furthermore, this method is very easy to use. This makes it suitable for both large and small-scale manufacturing operations. The benefits of scribe laser dicing are discussed below. The article also describes how to use the technology.

First, the scribing process is carried out by using a pulsed Nd-YAG laser whose wavelength (1064 nm) matches the band gap in silicon. Next, the laser beam is focused on a wafer surface, which contains a defect region of approximately 10 um in width. A water-cooled substrate is used to prevent particle contamination and thermal damage. Once the laser beam has cut through the wafer, it travels along the scribed pattern to form a chip.

Step dicing

The first step of semiconductor wafer laser dicing is to focus a pulsed Nd-YAG laser beam with wavelength 1064 nm, which matches the silicon band gap. The beam is focused at various depths in the wafer to inscribe defect regions of 10 um. The optical micrograph below shows the cleavage plane. Once the laser beam is focused, multiple scans are performed to inscribe defects in the semiconductor wafer.

The process can then proceed to the next step, measuring defects and groove widths. The laser beam 510 induces defects in the semiconductor wafer by passing through dicing tape. The semiconductor wafer is then remounted on dicing tape with the back side on top. Blade saw 514 is used to form grooves in the front surface. Step dicing is a valuable part of the semiconductor wafer laser dicing process and provides the most accurate results.

Stealth dicing

Many semiconductor manufacturers are using stealth laser dicing to cut large volumes of MEMS. This process is highly accurate and straight, and is becoming the standard for high-volume semiconductor dicing. However, the process may not be appropriate for all wafers, such as those covered with film or with patterns. In this case, a stealth laser dicing process is the best choice.

This process requires a high-powered laser to modify the semiconductor wafer to create a chip. In the case of monocrystalline silicon, the laser emits a high-energy pulse of 1064 nm, which is close to the silicon band gap. The laser beam is focused at different depths on the wafer, thereby inscribing a defect region of 10 um in width.

Cost of laser dicing

The cost of semiconductor wafer laser dicing depends on the amount of chipping or cracking that occurs. In general, dicing processes that use laser energy to dig out silicon result in excellent chip quality with a minimum amount of cracking or chipping. Conventional laser dicing generates grooves on the wafer’s surface, resulting in physical damage to the wafer. When the laser energy is turned off, silicon debris sticks to the front surface of the wafer.

Another method is laser ablation. Lasers emit light waves of various wavelengths, allowing for faster dicing. However, the laser also produces heat that damages circuitry on chips and degrades the mechanical strength of each die. Laser dicing is not a cheap process and requires a high-end semiconductor manufacturing facility. Nevertheless, the benefits far outweigh the costs. Moreover, it is also faster than blade dicing.

 

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