Circuit Board Corner Hollows for Warpage Reduction
Solution Overview
Problem
Conventional semiconductor chip packages experience warpage due to mismatches in coefficients of thermal expansion, leading to increased z-height and potential solder joint defects, which is a challenge in thin form factor devices like smartphones and tablets.
Innovation Solution
The implementation of circuit boards with four corner hollows to reduce warpage and stiffen the substrate, allowing for a thinner form factor while maintaining electrical performance and preventing solder joint defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional substrates are used without corner hollows, then the substrate provides basic structural support, but warpage occurs due to mismatches in coefficients of thermal expansion
Solution Approach 1:
The substrate corners are segmented by creating hollows that divide the continuous corner regions into separate zones. This segmentation allows independent movement and stress distribution at each corner, preventing cumulative warpage effects across the entire substrate while maintaining overall structural stability.
Solution Approach 2:
Corner hollows are positioned asymmetrically at the four corners of the substrate, creating an asymmetric structural pattern that specifically targets corner warpage issues. This asymmetric design allows the substrate to better accommodate thermal expansion mismatches at critical corner regions without compromising overall structural integrity.
2Length of stationary object
If the circuit board is made thinner to reduce z-height, then the form factor is improved for portable devices, but the substrate becomes more susceptible to warpage
Solution Approach 1:
Instead of uniformly thickening the entire substrate, corner hollows are strategically positioned only at the four corner regions where warpage most commonly occurs. This localized structural modification provides targeted warpage resistance at critical areas while maintaining the overall thin profile and low z-height of the circuit board.
Solution Approach 2:
The corner hollows create a three-dimensional structural feature on an otherwise two-dimensional thin substrate. By introducing vertical dimensionality through the hollow cavity structure at corners, the design achieves enhanced warpage resistance without significantly increasing the overall z-height of the circuit board.
3Reliability
If corner hollows are added to the circuit board, then warpage is reduced and z-height is decreased, but the manufacturing process becomes more complex
Solution Approach 1:
The corner hollows are designed to be formed during the initial substrate manufacturing process rather than as a separate post-processing step. This preliminary action integrates the warpage prevention feature into the core fabrication workflow, avoiding additional manufacturing complexity while achieving the desired structural modification.
Solution Approach 2:
The same corner hollow design pattern is replicated at all four corners of the substrate, using a standardized template approach. This copying strategy simplifies manufacturing by allowing the use of identical tooling and process parameters for each corner, reducing overall manufacturing complexity despite the added feature.
Data Source
AI summary
A method of manufacturing is provided that includes singulating a circuit board from a substrate of plural of the circuit boards, wherein the circuit board is shaped to have four corner hollows. The corner hollows may be various shapes.