Embedded PCB Component Alignment via Laser Drilling
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Solution Overview
Problem
Face-down embedding methods in printed circuit boards face issues with moisture absorption and inhomogeneities in adhesives, leading to unreliable component contacting, while face-up methods suffer from inaccuracies in alignment and drilling due to the lack of direct relationship between assembly and contacting positions, limiting miniaturization.
Innovation Solution
A method involving a lower conductor foil with alignment marks, adhesive application, face-up component placement, embedding in an insulating layer, and precise laser drilling to create contact holes, achieving high accuracy and reliability with direct alignment and reduced moisture issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If face-down embedding method is used, then component contacts can be directly connected to metallic conductor layer, but moisture absorption and adhesive inhomogeneities cause unreliable contacting
Solution Approach 1:
The patent inverts the conventional face-down embedding approach by using face-up embedding, where the component's contact side faces upward instead of being glued to the conductor layer. This inversion eliminates the moisture and adhesive issues that plague face-down methods, as the contact surfaces remain exposed and accessible for direct laser drilling without being trapped under adhesive layers.
Solution Approach 2:
The patent extracts the component from the adhesive-bonded configuration and places it on the conductor layer surface with contact sides facing upward. This extraction removes the harmful interaction between moisture/adhesive and the contact surfaces, allowing direct laser access to the contact pads for reliable electrical connection.
2Object-affected harmful factors
If face-up embedding method is used, then moisture and adhesive problems are eliminated, but alignment accuracy between assembly and drilling positions deteriorates to ±60 μm
Solution Approach 1:
The patent introduces alignment marks as an intermediary reference system that mediates between the component placement position and the laser drilling position. These marks serve as a common reference framework that enables precise alignment (±20 μm) between the assembly machine and laser drilling device, overcoming the alignment inaccuracies of conventional face-up methods.
Solution Approach 2:
The patent implements a feedback mechanism where alignment marks are detected by both the assembly machine and laser drilling device. The system uses these detected mark positions to calculate and adjust the relative positioning, providing feedback that corrects alignment deviations and achieves high precision contact hole placement.
3Measurement precision
If alignment marks are detected from below for component assembly, then assembly positioning is accurate, but subsequent laser drilling alignment from below causes inaccuracies
Solution Approach 1:
The patent inverts the detection direction for alignment marks - instead of detecting marks from below as in conventional methods, the alignment marks are detected from above by both the assembly machine and laser drilling device. This inversion ensures that both operations use the same reference perspective, eliminating cumulative alignment errors and achieving consistent high precision throughout the 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
This method achieves significantly higher accuracy in contact hole production, reducing inaccuracies to ±20 μm and ensuring high packing density and reliability, while minimizing costs and processing time.
Implementation Method 1
a lower conductor foil (1), which is fixed by gluing to a first metallic support layer (2)
Implementation Method 2
curing of the adhesive of the at least one adhesive layer
Implementation Method 3
drilling holes registered on the alignment marks using a laser to the contact surfaces of the component
Implementation Method 4
applying a conductor layer at least on the upper side of the structure, making contacts in the bores to the connection surfaces of the component
Data Source
Figure 1~4
Figure 5~8
Figure 9~10
AI summary
The invention relates to a method for embedding at least one component into a printed circuit board, comprising the steps of providing a lower metallic conductor foil (1) applied on a first metallic supporting layer (2), forming recessed alignment marks (3) in the conductor foil (1), applying an adhesive layer (4) in a registered manner in relation to the alignment marks (3), and placing a component (5) with the rear side thereof on the adhesive layer (4) with connection areas (6) facing upwards, curing the adhesive layer, embedding the component (5) into an insulating layer (11), applying a metallic upper conductor foil (9) and an upper metallic supporting layer (10), consolidating the construction, removing the supporting layers (2, 10), exposing the alignment marks (3) of the lower conductor foil (1) by removing the insulating layer (11), producing cutouts (12) ending at the lower conductor foil (1), producing holes (13) to the connection areas (6) of the component (5) in a registered manner in relation to the alignment marks, and applying a conductor layer to the top side of the construction, producing contact-connections (14) in the holes (13) to the connection areas (6) of the component (5), and structuring the conductor layer for producing conductor tracks (15).