Multilayer Wiring Board Reference Pattern Capacitance Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for testing multilayer wiring boards require known normal electric capacitance between signal lines and grounded layers, which is either obtained from acceptable products or unreliable calculations, making it costly and prone to production quality fluctuations.
Innovation Solution
A multilayer wiring board with reference patterns of predetermined length, allowing for accurate calculation of normal electric capacitance without preparing acceptable products, by measuring and using area ratios of reference patterns to determine the capacitance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If normal electric capacitance is obtained from acceptable products, then measurement precision is improved, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent applies preliminary action by incorporating reference patterns into the multilayer wiring board structure during the manufacturing process. These reference patterns are formed in advance as part of the board fabrication, enabling later extraction of normal capacitance values without requiring separate acceptable products for calibration. This eliminates the need to set aside acceptable products for measurement purposes, thereby improving productivity while maintaining measurement precision.
Solution Approach 2:
The patent uses reference patterns as copies or representations of the actual wiring paths. Instead of measuring the actual wiring paths directly (which would require acceptable products), the reference patterns serve as standardized copies that can be measured to obtain normal capacitance values. These reference patterns are designed with known dimensions and configurations, allowing them to represent the expected electrical characteristics of the wiring paths without requiring physical acceptable products for measurement.
2Ease of manufacture
If normal electric capacitance is calculated using production quality fluctuations, then manufacturing cost decreases, but measurement precision deteriorates
Solution Approach 1:
The patent replaces the mechanical approach of physically measuring acceptable products with an electrical measurement approach using reference patterns. Instead of relying on calculations that are influenced by mechanical variations in production quality, the system uses electrical capacitance measurements of reference patterns with known geometries. This substitution eliminates the impact of production quality fluctuations on the measurement process, improving precision while maintaining ease of manufacture.
Solution Approach 2:
The patent changes the parameters used for capacitance determination from calculated values based on production dimensions to measured electrical values from reference patterns. By using reference patterns with controlled geometries and measuring their actual capacitance values, the system compensates for production quality fluctuations. This parameter change from calculated to measured values ensures that the normal capacitance values reflect actual electrical characteristics rather than being influenced by manufacturing variations.
3Measurement precision
If reference patterns are added to multilayer wiring board, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the reference patterns with the existing multilayer wiring board structure. The reference patterns are integrated into the same conductor layers and insulating layers as the actual wiring paths, combining multiple functions into a single unified structure. This merging approach allows the reference patterns to be measured alongside the wiring paths without requiring separate test structures or additional components, thereby improving measurement precision while minimizing the increase in device complexity.
Solution Approach 2:
The reference patterns serve multiple functions: they act as both structural elements of the wiring board and as measurement references for capacitance calibration. This multi-functionality reduces the need for separate dedicated reference structures, thereby limiting the increase in device complexity. The same conductor layers that form the wiring paths also contain the reference patterns, allowing a single structure to fulfill both signaling and measurement purposes.
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
Enables accurate determination of normal electric capacitance without influencing production quality fluctuations, reducing costs and ensuring reliable testing for multilayer wiring boards.
Implementation Method 1
measuring, with a measuring device 28, an electric capacitance between the test pad 78 and the uppermost wiring pattern 60
Data Source
AI summary
A multilayer wiring board has a ceramic substrate, on which a multilayer wiring section is formed. One of the conductor layers has a grounded pattern. Each of the conductor layers has a reference pattern, which is usable as a standard in calculation of an electric capacitance. An electric capacitance is measured between the grounded pattern and the three-dimensional wiring path. On the other hand, a theoretical electrical capacitance is calculated on the basis of a reference value of electric capacitance which has been measured between the reference pattern and the grounded pattern. The measured value for the wiring path is compared to the calculated value to determine whether the three-dimensional wiring path is good or bad. As the multilayer wiring section has the reference patterns, the electric capacitance for the normal wiring path can be obtained by calculation without preparing the normal acceptable product.