MARCH 2025
Dicing and Die Prep
Semiconductor dicing and die preparation are essential and intricate steps in the semiconductor fabrication process. These steps are crucial for ensuring that individual chips, also known as dies, are meticulously separated from the wafer and adequately prepared for the subsequent stages of final packaging. The precision and care taken during these processes are paramount, as they directly influence the overall yield, performance, and reliability of the final semiconductor devices. A well-executed dicing and die preparation phase can lead to higher quality and more efficient semiconductor products, which are vital for meeting the demanding standards of modern electronic applications. This phase involves a series of detailed procedures that must be carefully managed to prevent defects and ensure that each die meets the necessary specifications for its intended use.
Q: What are the key steps in die prep?
A: Die prep encompasses all processes that take an IC from a wafer after test and into die form prior to assembly. The primary die prep steps are:
- Wafer Mounting
- Wafer Backgrinding (Thinning)
- Wafer Cleaning
- Wafer Dicing (Singulation)
- Die Inspection
- Die Sorting & Picking
- Die Bonding (if part of the process)
Q: Why is die prep important?
A: Die prep is a crucial step in semiconductor manufacturing that directly impacts the reliability, yield, and performance of the final packaged devices.
- Ensures high-quality, defect-free dies for packaging
- Minimizes mechanical stress and contamination
- Enables precise handling for downstream semiconductor assembly.
Q: What is backgrind?
A: Wafer thinning, or backgrind, is a process used to reduce the thickness of a semiconductor wafer after front-end processing is complete. This step is essential for advanced packaging, ensuring the final semiconductor device meets size, weight, and thermal requirements.
Q: What are the most common forms of backgrind?
A: Each backgrind method is chosen based on wafer thickness requirements, material properties, and end-use application. The most common forms of backgrind include:
- Conventional Mechanical Backgrinding
- Wet Etch
- Chemical Mechanical Planarization (CMP)
- Plasma or Chemical Etching
- Laser Assisted Backgrinding
Q: What kind of backgrinding does Integra use?
A: Conventional Mechanical Backgrinding
Q: What does microgrind or polish do to the wafer?
A: Die strength and smoothness can be increased based on grit/slurry selection (increasing smoothness), while also decreasing warpage and subsurface damage.
Q: What are the most common types of wafer singulation?
A: The most common methods of wafer singulation are mechanical dicing are:
- Laser dicing
- Scribe and break
- Dice Before Grind (DBG)
Q: What determines the best method for wafer singulation of my wafer?
A: Wafer singulation is the process of separating individual semiconductor dies from a processed wafer. The choice of singulation method depends on factors such as:
- Wafer material
- Thickness
- Die size
- Yield requirements
Q: What are some keys when considering street widths of my wafer and subsequent dicing?
A: The following are keys when considering street width:
- A typical street width for mechanical dicing is in the neighborhood of 80um
- Street width governs the blade/kerf width
- Total thickness (including bumps) determines blade exposure
- Blade exposure is restricted by blade width
- The narrower the blade the smaller the exposure
- Therefore, for wafers with narrow streets, thinning is required
Q: I have a multi-project wafer, what are some considerations?
- Indexing is consistent across all die in a reticle in order to singulate without sacrificing die
- Inconsistent indexing between die in a reticle would require die to be sacrificed or cut through, in order to salvage the target die
- If all die in an inconsistent reticle are required to be saved, then remounting is necessary