Shallow Scribe-Line Trench Dicing for Planar Die Separation
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Solution Overview
Problem
The increasing complexity of integrated circuit packages, which integrate multiple device dies and require advanced manufacturing techniques, faces challenges in efficient die separation and bonding, leading to issues such as delamination and non-planar surfaces during the dicing process.
Innovation Solution
A method involving the formation of a single shallow trench in scribe lines of a wafer, followed by laser grooving and sawing, reduces the space needed for die separation and maintains a planar surface, thereby minimizing delamination and facilitating reliable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If traditional deep trenches are formed in scribe lines for die separation, then die separation can be achieved, but the space needed for sawing increases and chip area is reduced
Solution Approach 1:
The trench formation process is segmented into two stages: first forming a shallow trench etching into the interlayer dielectric, then performing laser grooving to create the remaining depth. This segmentation allows the etching process to stop before reaching the semiconductor substrate, preserving chip area while still enabling effective die separation when combined with laser grooving.
Solution Approach 2:
The shallow trench is formed as a preliminary action before laser grooving. This preliminary etching creates a controlled starting point that guides the laser grooving process and removes material more efficiently, while limiting the etching depth to protect the semiconductor substrate and maximize chip area.
2Reliability
If deep trenches are etched through the wafer, then complete die separation is achieved, but delamination risk increases and surface planarity is compromised
Solution Approach 1:
Instead of etching through the entire wafer depth, the process applies partial action by etching only a shallow trench into the interlayer dielectric layer. This partial etching, when combined with laser grooving, achieves sufficient die separation without creating deep trenches that would compromise structural integrity and increase delamination risk.
Solution Approach 2:
The shallow trench acts as an intermediary structure that facilitates the laser grooving process. By providing a pre-formed channel in the interlayer dielectric, the trench guides the laser beam and enables controlled material removal without requiring deep mechanical etching that would compromise wafer integrity.
3Manufacturing precision
If multiple trenches are formed in each scribe line, then die separation is enhanced, but manufacturing complexity and residue removal difficulty increase
Solution Approach 1:
The process extracts only the essential function of trench formation by creating a single shallow trench rather than multiple deep trenches. This extraction of the core function simplifies the manufacturing process and reduces the amount of material that needs to be removed, making residue removal easier while still achieving effective die separation when combined with laser grooving.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for wider chip areas and longer delamination propagation paths, enhancing the reliability and ease of residue removal, while maintaining a planar surface for effective bonding and encapsulation.
Implementation Method 1
performing a laser grooving process to form a second trench extending from the top surface further down into the wafer
Data Source
AI summary
A method includes etching a portion of a wafer to form a first trench in a scribe line of the wafer, wherein the scribe line is between a first device die and a second device die of the wafer. After the etching, a top surface of the portion of wafer in the scribe line is underlying and exposed to the first trench, and the first trench is between opposing sidewalls of the wafer. A laser grooving process is then performed to form a second trench extending from the top surface further down into the wafer, and the second trench is laterally between the opposing sidewalls of the wafer. A die-saw process is then performed to saw the wafer. The die-saw process is performed from a bottom of the second trench, and the die-saw process results in the first device die to be separated from the second device die.