Angled Laser Drilling for Single-Layer Wafer Pad Relocation
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Solution Overview
Problem
The existing wafer-level packaging processes for semiconductor chips are inefficient and prone to defects due to the need for multiple redistribution layers, which increase manufacturing complexity, thickness, and the risk of delamination, limiting the ability to shrink package size and improve production throughput.
Innovation Solution
Employing a multi-axis laser drill to drill off-vertical holes through a single redistribution layer, allowing for the relocation of input/output contact pads with fewer operations and greater flexibility, reducing the need for multiple layers and improving manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple redistribution layers are used to relocate I/O contact pads, then the contact pads can be relocated to different positions, but the manufacturing complexity and device thickness increase
Solution Approach 1:
The patent introduces angular drilling at non-orthogonal angles (e.g., 45 degrees) through the redistribution layer, adding a dimensional aspect to the hole formation process. This allows contact pads to be relocated laterally by controlling the drill angle, achieving relocation capability without stacking multiple redistribution layers vertically.
Solution Approach 2:
The patent changes the drilling angle parameter from the conventional orthogonal (90 degrees) to oblique angles (e.g., 45 degrees). By controlling the angular parameter of the laser drill, the contact pad position can be adjusted laterally, providing relocation capability while maintaining a single redistribution layer structure.
2Adaptability or versatility
If multiple redistribution layers are used to relocate I/O contact pads, then the contact pads can be relocated to different positions, but the package thickness increases
Solution Approach 1:
The patent uses angular drilling to exploit the angular dimension for lateral contact pad relocation. Instead of adding vertical layers to achieve relocation, the method uses inclined holes at controlled angles to shift contact pad positions horizontally, thereby avoiding thickness increase.
Solution Approach 2:
Instead of using vertical stacking (adding layers in the vertical direction) to achieve lateral relocation, the patent inverts the approach by using inclined drilling where the angle control provides lateral displacement. This reverses the conventional relationship between layer count and relocation capability.
3Adaptability or versatility
If multiple redistribution layers are used to relocate I/O contact pads, then the contact pads can be relocated to different positions, but the risk of delamination increases
Solution Approach 1:
The patent extracts the relocation function from the vertical stacking of multiple redistribution layers and implements it through angular drilling in a single layer. This eliminates the need for additional layer interfaces, thereby removing the delamination risk associated with multiple bonded layers.
Solution Approach 2:
The patent inverts the conventional approach of using multiple layers for relocation. Instead of adding layers to achieve lateral displacement, it uses angular drilling in a single layer, thereby eliminating the interfaces that would be prone to delamination.
4Ease of manufacture
If conventional orthogonal drilling is used through the redistribution layer, then the manufacturing process is simple, but the contact pads cannot be relocated effectively
Solution Approach 1:
The patent modifies the drilling angle parameter from orthogonal (90 degrees) to oblique angles (e.g., 45 degrees). This parameter change enables lateral contact pad relocation while maintaining laser drilling as the core process, thus preserving manufacturing simplicity while gaining relocation capability.
Solution Approach 2:
The patent introduces dynamic angular control to the drilling process. The laser drill can adjust its angle dynamically to achieve different lateral displacement amounts, providing versatility in contact pad relocation while keeping the process relatively simple through automated angular positioning.
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 more efficient and defect-reduced relocation of contact pads, allowing for smaller form factors and increased production efficiency by drilling angled holes with precision, thus reducing the overall thickness and complexity of the wafer-level package.
Implementation Method 1
drilling, with a multi-axis laser drill, a hole along an axis through the redistribution layer
Data Source
AI summary
A method of relocation of input/output (I/O) contact pads in a wafer-level package is provided. A method of manufacturing a wafer-level package can include: forming a redistribution layer on a wafer having a contact pad disposed thereon, where the wafer defines a plane along a major horizontal surface on which the contact pad is disposed; drilling, with a multi-axis laser drill, a hole along an axis through the redistribution layer to reach the contact pad, where the axis of the hole through the redistribution layer is at an angle relative to the plane that is neither parallel nor orthogonal; and forming a contact extending from the contact pad, through the hole through the redistribution layer, to a position on the redistribution layer.