Ultra Thin Coreless Substrate Debond Layer
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Solution Overview
Problem
Conventional electronic packaging substrates face challenges in achieving higher density and lower profile (z-height) designs, particularly in mobile devices, where the reduction of core layer thickness and fabrication of coreless substrates are necessary to meet these demands, but existing methods are inefficient and often result in thicker, warpage-prone substrates.
Innovation Solution
A method for forming coreless substrates involves creating a debond layer on a carrier substrate with varying adhesion surfaces, forming a build-up structure, and attaching a support substrate, which allows for the carrier substrate to be detached, enabling the production of ultra-thin substrates with a build-up structure less than 100 μm thick, and subsequent cutting into substrate strips, ensuring 'known good' substrates with reduced warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If core layer thickness is reduced to achieve lower profile packages, then z-height is reduced, but substrate strength and structural stability deteriorate
Solution Approach 1:
A carrier substrate is introduced as an intermediary support structure during fabrication. The carrier substrate provides mechanical strength and stability during the build-up process, allowing the core layer to be made extremely thin or eliminated entirely. The carrier acts as a temporary scaffold that is removed after the build-up structure is complete, resolving the contradiction between thin profile and structural strength.
Solution Approach 2:
The build-up structure is formed on the carrier substrate before the carrier is removed. This preliminary formation on a supported surface allows precise fabrication of thin structures that would be difficult to manufacture free-standing. The carrier enables the preliminary creation of ultra-thin coreless substrates that maintain integrity during subsequent processing steps.
2Quantity of substance
If coreless substrates are fabricated to achieve higher density packages, then packaging density is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct phases: forming the debond layer on the carrier, building up the structure on one side, attaching the support substrate, and finally separating the components. This segmentation allows each step to be optimized independently and simplifies the overall manufacturing complexity by breaking down the complex coreless substrate fabrication into manageable sequential operations.
Solution Approach 2:
The carrier substrate serves as a manufacturing intermediary that simplifies the fabrication of high-density coreless substrates. By providing a stable base during build-up and enabling controlled separation afterward, the carrier reduces the practical manufacturing complexity despite the advanced nature of coreless substrate requirements.
3Ease of manufacture
If debond layer with varying adhesion is used to enable carrier detachment, then ease of manufacture is improved, but manufacturing precision requirements increase
Solution Approach 1:
The debond layer is designed with spatially varying adhesion properties - stronger adhesion in some regions and weaker adhesion in others. This local quality differentiation allows the build-up structure to remain attached during fabrication while enabling controlled detachment of the carrier afterward. The varying adhesion zones provide both manufacturing ease and sufficient precision control.
Solution Approach 2:
The adhesion parameters of the debond layer are specifically controlled and varied across different regions. By adjusting adhesion strength as a controllable parameter, the process achieves both easy carrier removal where needed and secure attachment where required, balancing manufacturing ease with precision requirements.
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 enables the production of ultra-thin, coreless substrate strips that are verified as 'known good' with reduced warpage concerns, increasing assembly throughput and allowing for efficient shipment and use in BGA chip assembly, while maintaining compatibility with traditional BGA fabrication processes.
Implementation Method 1
The debond layer includes a first surface area and a second surface area on the carrier substrate, the first surface area surrounds the second surface area, and the first surface area has greater adhesion to the carrier substrate than the second surface area
Data Source
AI summary
Method of forming ultra thin coreless substrates are described. In an embodiment, the method utilizes a debond layer including high and low adhesion surface areas to the carrier substrate, and cutting through the low adhesion surface areas to remove a build-up structure from the carrier substrate. An electrical short layer may be formed as a part of or on the debond layer to facilitate electrical testing of the build-up structure prior to debonding, and aid in the formation a “known good” substrate on a support substrate.