Redistribution Layer Test Pattern for Through-Hole Inspection
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Solution Overview
Problem
In packaging technology, the stacking thickness of redistribution structures in different positions of a substrate can vary by several micrometers, making it difficult to ensure that through holes penetrate evenly through the dielectric layer. Additionally, there is no inline inspection method to determine the quality of patterned through holes in real time.
Innovation Solution
A package device with a redistribution layer that includes a test pattern comprising a conductive pattern formed of a conductive layer. The conductive pattern consists of sub-portions arranged along a direction, with increasing sizes, allowing for real-time inspection of the patterning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional through hole formation process is used, then through holes are formed in the dielectric layer, but it is difficult to ensure even penetration due to stacking thickness variation
Solution Approach 1:
The patent applies preliminary action by forming a test pattern structure before the actual through hole formation process. This test pattern includes a conductive layer with varying thickness that simulates the stacking thickness variation, allowing the patterning process to be optimized in advance. The test pattern is formed on a substrate with dielectric layers, and the conductive layer thickness is deliberately varied to pre-characterize the process window and establish process parameters that will ensure uniform through hole penetration across different stacking thicknesses.
Solution Approach 2:
The patent implements feedback by using the test pattern to measure and evaluate the patterning process performance. The test structure allows real-time monitoring of process quality parameters such as line width, thickness uniformity, and alignment accuracy. Based on the measurements obtained from the test pattern, process parameters are adjusted to compensate for stacking thickness variation, ensuring that the actual through hole formation process achieves the desired penetration uniformity and reliability.
2Measurement precision
If no inline inspection is performed, then production continues without interruption, but real-time quality determination of patterned through holes is not possible
Solution Approach 1:
The test pattern is formed in advance as part of the substrate preparation, before the actual production batches are processed. This preliminary structure serves as a built-in reference for subsequent inline inspection, eliminating the need for separate inspection setups or process interruptions. The test pattern includes features with known dimensions and positions that can be quickly measured by inline inspection equipment to establish process baseline and monitor real-time quality.
Solution Approach 2:
The test pattern structure serves itself as the inspection target, eliminating the need for external reference standards or additional measurement artifacts. The conductive layer with varying thickness and the associated dielectric structures create self-referential features that can be directly measured to determine process quality. The test pattern inherently contains the information needed to evaluate patterning performance, allowing the system to self-diagnose and self-adjust without external intervention or process interruption.
Data Source
AI summary
A package device is provided and includes a redistribution layer. The redistribution layer includes a first dielectric layer, a conductive layer and a second dielectric layer, and the conductive layer is disposed between the first dielectric layer and the second dielectric layer. The redistribution layer has a test pattern including a conductive pattern, and the conductive pattern is formed of the conductive layer. The conductive pattern comprises a plurality of sub-portions arranged along at least one direction, and sizes of the plurality of sub-portions increase sequentially along the at least one direction.