Circuit Board Bonding With Release-Layer Support and Underfill
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Solution Overview
Problem
Existing methods for producing circuit boards with narrow-pitch connection terminals and fine wiring patterns face issues such as high costs due to expensive silicon wafers, yield reduction from production defects, and defects caused by warpage or strain in FC-BGA circuit board components.
Innovation Solution
A method involving a second circuit board component with a finer wiring pattern bonded to a first circuit board component, using a support with a release layer for easy detachment, and filling a sealing resin gap between components to improve yield and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a silicon interposer is used to achieve narrow-pitch connection terminals and fine wiring patterns, then manufacturing precision is improved, but device complexity and cost increase due to expensive silicon wafers and preprocessing equipment
Solution Approach 1:
The patent replaces expensive silicon wafers with a disposable support substrate that can be easily removed after bonding. The support substrate serves its purpose during the bonding process and is then discarded, eliminating the need for costly silicon wafer preparation and specialized equipment while achieving the same fine wiring pattern bonding capability
Solution Approach 2:
The patent extracts the essential function of the silicon interposer (providing a stable surface for fine wiring pattern bonding) and separates it from the expensive silicon material requirements. By using a simple support substrate with release layer, the patent removes the complexity of silicon wafer preprocessing while maintaining the core bonding functionality
2Manufacturing precision
If chemical mechanical polishing (CMP) is performed to flatten the FC-BGA circuit board component surface for fine wiring patterns, then manufacturing precision is improved, but productivity decreases due to yield reduction from production defects and warpage
Solution Approach 1:
The patent performs the bonding of fine wiring patterns to the support substrate before mounting the semiconductor elements on the FC-BGA component. This preliminary bonding action on a stable, flat support surface eliminates the need for subsequent CMP processing of the FC-BGA component, avoiding warpage and production defects while maintaining surface flatness requirements
Solution Approach 2:
Instead of flattening the FC-BGA component surface through CMP and then forming wiring patterns, the patent inverts the sequence by first forming the fine wiring patterns on a stable support substrate and then bonding this assembly to the FC-BGA component. This eliminates the need for CMP processing of the FC-BGA component and avoids associated defects
3Ease of manufacture
If a support is used to form the substrate with fine wiring pattern layer, then ease of manufacture is improved, but reliability decreases due to defects in the support release step
Solution Approach 1:
The patent introduces a release layer as an intermediary between the support substrate and the fine wiring pattern layer. This release layer enables easy and defect-free removal of the support substrate after bonding, as it provides a controlled interface that allows clean separation without damaging the bonded components. The release layer acts as a mediator that facilitates manufacturing ease while maintaining reliability
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 method enhances the yield of circuit board production by simplifying the support release process, reducing defects, and maintaining high productivity while maintaining transmission characteristics.
Implementation Method 1
a second circuit board component preparation step of preparing the second circuit board component by performing a step of forming first electrodes on a support via a release layer for bonding to the semiconductor elements
Implementation Method 2
a resin supply step of filling a sealing resin in a gap between the first circuit board component and the second circuit board component
Implementation Method 3
a photomask layer formation step of forming a photomask layer on the conductive resin; and a pattern formation step of removing a portion of the photomask layer and the conductive resin
Data Source
Figure 1~2
Figure 3A~3E
Figure 3F~3J
AI summary
There is provided a method of producing circuit boards, including a bonding step of bonding joints (18a) of a BA circuit board component (1) with respective joints (18b) of an interposer (3), followed by a resin supply step of filling an underfill (2A) in a gap between the FC-BGA circuit board component (1) and the interposer (3), a resin curing step of curing the underfill (2A), and a support release step of releasing a support (5) from the interposer (3), which are performed through a sequence of the support release step, the resin supply step, and the resin curing step.