Ceramic Substrate Warpage Control via Electrode Volume Balancing
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Solution Overview
Problem
Ceramic substrates often warp due to differences in metal layer volumes on opposite surfaces, leading to high defect rates and production losses, especially when the volume ratio exceeds 75-85%, making it difficult to maintain a stable substrate under high temperature environments.
Innovation Solution
A method involving the formation of first and second electrode layers on opposite surfaces of a ceramic base material, with additional etching to control the thickness of the second electrode layer, ensuring a volume ratio of 95% ± 10% to prevent warpage, thereby eliminating volume differences and stabilizing the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If metal layers are formed on opposite surfaces of ceramic base material with different areas or thicknesses, then the substrate can accommodate pattern arrangements, but warpage occurs when the volume ratio exceeds 75-85%
Solution Approach 1:
The patent changes the volume parameter of the metal layers by controlling their thickness and area during the brazing process. By adjusting these parameters to maintain a volume ratio within 75-85%, the substrate maintains flatness while still accommodating different pattern arrangements on opposite surfaces.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and controlling the volume ratio of metal layers before the brazing process completes. The thickness and area of metal layers are predetermined to ensure the volume ratio stays within the safe range, preventing warpage before it occurs.
2Stability of the object's composition
If the thickness of the base material is increased to reduce warpage, then substrate flatness improves, but manufacturing cost increases and the thickness ratio with metal layers becomes unbalanced
Solution Approach 1:
Instead of changing the base material thickness, the patent changes the parameters of the metal layers (thickness and area) to control their volume. By maintaining the volume ratio within 75-85%, the patent achieves flatness control without increasing manufacturing cost or disrupting the conventional thickness ratio balance.
3Stability of the object's composition
If additional etching is performed to control the volume ratio of electrode layers, then warpage control improves, but process complexity increases
Solution Approach 1:
The patent applies preliminary action by establishing the target volume ratio range (75-85%) before the etching process. This allows the additional etching to be performed with a clear objective, controlling the volume of electrode layers to prevent warpage while maintaining process efficiency.
Solution Approach 2:
The patent uses feedback by calculating the volume ratio of electrode layers and comparing it against the target range. Based on this feedback, the etching process is adjusted to achieve the desired volume balance, ensuring warpage control while optimizing the additional process step.
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 effectively reduces substrate warpage, decreases defect rates, and enhances productivity by maintaining substrate flatness even under high temperature conditions, as demonstrated by achieving acceptable flatness and minimal variation after reflow at 350°C.
Implementation Method 1
manufacturing of the ceramic AMB substrate involves brazing an active metal to a ceramic base material to form a layer and brazing metal to a brazing layer
Implementation Method 2
forming a first electrode layer by etching the metal layer on one surface of the ceramic base material; forming a second electrode layer by etching the metal layer on the other surface
Data Source
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AI summary
The present invention relates to a method of producing a ceramic substrate, the method including: joining a metal layer to each of opposite surfaces of a ceramic base material; forming, on the metal layers, a first electrode layer and a second electrode layer having a larger volume than the first electrode layer; calculating the volumes of the first and second electrode layers; and controlling a thickness of the second electrode layer, thereby controlling warpage which may occur due to a difference between the volumes of the first and second electrode layers. The present invention can reduce the defect rate of a ceramic substrate by controlling warpage that may occur due to the difference in volume taken up by the metal layers on the opposite surfaces of the base material.