Package Substrate Edge Thinning to Prevent Dicing Cracks
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Solution Overview
Problem
Packaging substrates made of brittle core substrates are prone to breakage due to thermal stress during or after dicing, leading to cracks and potential splitting, especially when glass substrates with thicknesses over several tens of micrometers are used in laminates.
Innovation Solution
A packaging substrate with a core substrate, insulating layers, and wiring layers, where the insulating layer is partially thinned at the outer peripheral portion to create a thin layer portion with a width of 120 µm or more, reducing tensile stress and preventing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dicing blade is used to cut the metal layer on the core substrate, then the wiring substrate can be diced into pieces, but cutting ability of the dicing blade decreases due to clogging, making cracks more likely to occur at the cut surface
Solution Approach 1:
The patent extracts and removes the metal layer from the outer peripheral portion of the core substrate before dicing. This prevents the metal layer from clogging the dicing blade during cutting, thereby maintaining blade cutting ability and preventing cracks at the cut surface while still allowing the wiring substrate to be diced into pieces.
Solution Approach 2:
The patent performs preliminary removal of the metal layer at the outer peripheral portion before the dicing process. This preliminary action prevents the metal layer from interfering with the dicing blade during cutting, ensuring clean cuts without cracks while maintaining productivity.
2Reliability
If the core substrate is made of brittle materials with good electrical properties, then electrical performance is improved, but the core substrate is likely to be broken due to impact during dicing and thermal stress
Solution Approach 1:
The patent extracts and removes the metal layer from the outer peripheral portion of the brittle core substrate before dicing. This eliminates the source of impact-induced cracks during cutting, allowing brittle materials with good electrical properties to be used without fear of breakage during the dicing process.
Solution Approach 2:
The patent applies preliminary anti-action by removing the metal layer that would cause harmful impact during dicing. This prevents the formation of minute cracks at the cut surface that would lead to breakage of the brittle core substrate, thereby protecting the substrate's strength while maintaining its electrical properties.
3Ease of manufacture
If the insulating layer is not thinned at the outer peripheral portion, then the structure is simple and manufacturing is easier, but tensile stress from thermal expansion differences causes breakage of the core substrate
Solution Approach 1:
The patent applies local quality by thinning the insulating layer specifically at the outer peripheral portion where thermal stress is concentrated, while maintaining the full thickness at other areas. This localized modification reduces tensile stress from thermal expansion differences at the critical outer peripheral region, preventing core substrate breakage without significantly complicating the overall manufacturing process.
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
The solution effectively prevents breakage of the core substrate cut surface during temperature changes, enhancing the reliability of the packaging substrate by reducing thermal stress and protecting both surfaces from chipping during the dicing and subsequent processes.
Implementation Method 1
the difference in the linear expansion coefficient increases the difference in expansion between the resin layers, the wiring layers and the core substrate if there is a change in temperature. In such a case, it is known that stress is applied to an outer peripheral portion of the core substrate.
Data Source
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AI summary
The present invention provides a packaging substrate that prevents breakage of a cut surface of a core substrate during fabrication of the packaging substrate by dicing a wiring substrate into pieces, and a method of fabricating the same. The packaging substrate according to the present invention is a packaging substrate including: a core substrate; an insulating layer formed on one surface or each of both surfaces of the core substrate; and one or more wiring layers formed on the insulating layer and/or embedded in the insulating layer. The packaging substrate has a thin layer portion where the insulating layer is partially thinned at an outer peripheral portion of the insulating layer.