Solder Paste Cylinders for Circuit Board Thermal Warpage
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Solution Overview
Problem
Existing methods for connecting circuit boards using solder balls are unreliable, expensive, and prone to connection failure due to thermal expansion and warpage during the melting process.
Innovation Solution
The method involves applying solder paste cylinders to terminal contacts on one circuit board substrate and aligning the terminal contacts of a second substrate on top of the solder paste cylinders, allowing for flexible expansion and compression during thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solder balls are used for connecting circuit boards, then more solder paste can be used per connection, but the connection becomes unreliable due to thermal expansion and warpage during melting
Solution Approach 1:
The patent changes the geometric parameters of the solder connection from spherical (solder balls) to cylindrical (solder paste cylinders), and modifies the material state from pre-formed solid balls to applied paste that can be controlled in shape and volume. This allows maintaining sufficient solder paste quantity while creating a more reliable connection that accommodates thermal expansion.
Solution Approach 2:
The invention introduces dynamic adaptability by allowing the solder paste cylinders to be applied with controlled dimensions that can accommodate thermal expansion during melting. The cylindrical shape and paste application method enable the connection to adapt to dimensional changes during the heating process, preventing connection failure.
2Reliability
If solder balls are arranged using ball grid arrays, then discrete electrical connections are established, but the process becomes expensive and complex
Solution Approach 1:
The patent replaces the complex mechanical ball grid array arrangement system with a simpler solder paste application process. Instead of using specialized equipment to place and arrange pre-formed solder balls, the invention uses standard solder paste application methods to create cylindrical connections directly, significantly reducing device complexity while maintaining electrical connection reliability.
Solution Approach 2:
The invention uses solder paste as a disposable material that is applied and then melted to create the connection. This eliminates the need for expensive, reusable ball grid array systems and positioning equipment, replacing them with a simpler, more cost-effective paste application approach that achieves the same electrical connection function.
3Manufacturing precision
If precise alignment and positioning systems are used for solder ball placement, then connection precision is improved, but production costs increase significantly
Solution Approach 1:
The patent replaces expensive mechanical positioning and alignment systems with a simpler solder paste application process. The paste can be applied using standard techniques that do not require complex alignment equipment, achieving sufficient manufacturing precision at lower production costs while maintaining connection quality.
4Reliability
If traditional soldering methods are used, then electrical connections are established, but thermal expansion causes warpage and connection failure
Solution Approach 1:
The invention changes the geometric parameters of the solder connection from spherical to cylindrical shape, and modifies the application method to allow controlled paste deposition. This creates a connection structure that better accommodates thermal expansion during heating, preventing warpage-induced connection failure while maintaining connection stability.
Solution Approach 2:
The patent applies solder paste in a controlled cylindrical form that provides a buffer or cushion against thermal expansion stresses. The paste application creates a connection structure that anticipates and accommodates the dimensional changes that occur during heating, preventing connection failure before it can occur.
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 maintains almost all connections during heating and cooling, reduces production costs by eliminating the need for precise alignment and fastening elements, and allows for high-density interconnect circuit boards with over 500 connections per square decimeter.
Implementation Method 1
melting the solder paste cylinders to form a mechanical and electrically conductive connection between the first terminal contacts of the first circuit board substrate and the second terminal contacts of the second circuit board substrate
Implementation Method 2
a connection made by solder balls can be destroyed if a distortion or warpage caused by thermal expansion during subsequent melting occurs in the two circuit board substrates
Data Source
AI summary
A method for producing a circuit board arrangement includes: providing a first circuit board substrate, providing a second circuit board substrate, arranged substantially planar-parallel to the first circuit board substrate, the first circuit board substrate having an underside and the second circuit board substrate having an upper face, the upper face and the underside being arranged opposite one another, providing first terminal contacts, applied to the underside of the first circuit board substrate, providing second terminal contacts, applied to the upper face of the second circuit board substrate, applying solder paste cylinders to the first terminal contacts, the solder paste cylinders applied to the first terminal contacts by a solder-paste application process with solder paste, the applied solder paste cylinders having in each case a solder-paste-cylinder upper face, and arranging the second terminal contacts of the second circuit board substrate on the solder-paste-cylinder upper faces of the solder paste cylinders.