Glass-Core IC Substrate Singulation with Laser-Weakened Cleavage Lines
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Solution Overview
Problem
Glass substrates used in IC packages are brittle, leading to challenges in singulation due to their mechanical fragility, which can result in micro-cracks, chipping, and coarse sidewalls during mechanical cutting, affecting the structural integrity and reliability of the final IC package.
Innovation Solution
A hybrid singulation strategy combining laser treatment with mechanical cutting, where laser-treated regions are created to weaken the glass along cleavage lines, allowing for reduced chipping and cracking during separation, and using a dicing tape-based expansion technique to minimize kerf widths and debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical cutting is used to singulate glass substrates, then singulation can be performed, but glass chipping and cracking occur due to brittleness
Solution Approach 1:
The glass substrate is pre-heated before mechanical cutting to reduce its brittleness and make it more ductile. This preliminary thermal treatment allows the subsequent mechanical cutting process to proceed without causing chipping or cracking, thereby maintaining structural integrity while enabling singulation.
Solution Approach 2:
The temperature parameter of the glass substrate is changed from ambient to elevated temperature. This parameter change transforms the mechanical properties of glass from brittle at room temperature to more ductile and workable at elevated temperature, allowing mechanical cutting without damage.
2Productivity
If mechanical cutting is used on glass substrates, then separation is achieved, but coarse sidewalls and micro-cracks are generated
Solution Approach 1:
The glass substrate is pre-heated before mechanical cutting to improve its ductility. This preliminary action enables the mechanical cutting process to produce smooth sidewalls and avoid micro-cracks, thereby achieving both high productivity and high manufacturing precision.
Solution Approach 2:
By changing the temperature parameter of the glass substrate to an elevated level, the material becomes more compliant during cutting. This results in clean cuts with fine edge finish quality while maintaining fast singulation speed.
3Reliability
If glass is used as core material for IC package substrate, then electrical properties and CTE matching are improved, but brittleness causes processing challenges
Solution Approach 1:
The temperature parameter of the glass substrate is elevated during processing to temporarily reduce its brittleness. This allows standard mechanical processing operations to be performed on glass substrates that otherwise have excellent electrical properties and CTE matching, thereby resolving the manufacturing difficulty without sacrificing material performance.
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 reduces glass chipping and cracking, improves the edge finish of sidewalls, and enhances the structural integrity and reliability of IC packages by minimizing defects during the singulation process.
Implementation Method 1
regions of a glass core are treated with a laser
Data Source
AI summary
An integrated circuit (IC) device comprises a substrate comprising a glass core. The glass core includes a first surface, a second surface opposite the first surface, a sidewall between the first surface and the second surface, and a corner region where the first sidewall meets the first surface. A first build-up layer is on at least the first surface. In some embodiments, the corner region comprises a recess and a dielectric material within the recess. In other embodiments, the corner region comprises a first compressive stress and the glass core comprises a second region. The second region comprises a second compressive stress. The first compressive stress is greater than the second compressive stress.