Semiconductor Singulation With Corner-Offset Laser Modifications
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Solution Overview
Problem
Existing semiconductor device manufacturing methods, such as plasma dicing, laser stealth dicing, and mechanical cutting, often cause damage to device edges, corners, and sidewalls during singulation, leading to reduced production yield and device performance.
Innovation Solution
Implementing laser stealth dicing with a modified process that avoids laser modifications adjacent to the corners of semiconductor devices by interrupting and resuming the laser path at intersections, creating gaps or offsets to prevent stress concentration and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional singulation methods (plasma dicing, laser stealth dicing, mechanical cutting) are used to separate semiconductor devices, then device separation is achieved, but damage occurs to device edges, corners, and sidewalls leading to reduced production yield
Solution Approach 1:
The patent applies preliminary action by creating a relief groove at the corner region before the main singulation cut. This groove is formed by the laser beam in advance, which redistributes stress and prevents crack propagation during subsequent device separation. The relief groove acts as a stress relief feature that protects corners from damage during the singulation process, thereby improving production yield without compromising device separation effectiveness.
Solution Approach 2:
The patent introduces an intermediary structure - the relief groove - between the laser beam and the device corner. This groove serves as a mediator that absorbs and redistributes the thermal and mechanical stress generated during laser singulation. By placing this intermediary feature at the corner region, the direct harmful impact of the laser on the device corner is reduced, preventing edge and corner damage while maintaining effective device separation.
2Ease of manufacture
If laser stealth dicing is used to singulate devices, then separation is achieved, but nonuniform stress concentration occurs at corners and intersections leading to cracking
Solution Approach 1:
The patent applies local quality by creating a relief groove specifically at the corner region where stress concentration occurs, rather than uniformly modifying the entire device structure. This localized modification addresses the specific stress problem at corners and intersections during laser singulation. The relief groove is formed only where needed - at the corner regions - to redistribute stress and prevent cracking, while leaving the rest of the device structure intact for effective separation.
Solution Approach 2:
The patent changes the physical parameters of the corner region by creating a relief groove with specific dimensions and depth. This groove modifies the local stress distribution parameters, transforming the high-stress concentration zone into a stress-relieved region. By controlling the groove's geometry (depth, width, shape), the patent optimizes stress redistribution to prevent cracking while maintaining the ability to achieve clean device separation along the singulation lines.
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
Reduces nonuniform stress and damage during singulation, resulting in higher production yields of functional semiconductor devices with smoother edges and improved reliability.
Implementation Method 1
The laser can selectively damage the wafer by using a laser beam at a certain wavelength emitted by the laser and by holding a head of the laser at a specified distance from the surface of the device wafer, condensing the beam at a set depth within the device wafer.
Data Source
AI summary
A semiconductor device can include a semiconductor substrate singulated from a device wafer having had multiple semiconductor devices formed thereon. The semiconductor substrate can include a first corner, a first sidewall extends in a first direction from the first corner, and a second sidewall extending in a second direction from the first corner. The first sidewall can include a first laser modification extending along the first direction and the second sidewall can include a second laser modification extending along the second direction. A portion of the second sidewall between the first corner and the second laser modification can (i) exclude laser modification, or (ii) the second laser modification can be offset from the first corner along the second direction.