Intermediate-Substrate Solder Paste Printing for High-Resolution Transfer
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Solution Overview
Problem
Current surface mount assembly processes face challenges in accurately applying solder paste due to issues with stencil accuracy, blade angle optimization, and high viscosity of solder paste, leading to defects such as solder bridges and insufficient solder application, especially at high printing speeds.
Innovation Solution
A two-step printing system is introduced, where an initial printing is done on an intermediate substrate followed by a high-resolution, low-debris transfer to a final substrate using a laser-assisted deposition system, with imaging and curing arrangements to ensure accurate deposition and minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If screen printing is used to apply solder paste, then the process is simple and cost-effective, but manufacturing precision deteriorates due to stencil accuracy issues, blade angle optimization, and paste leakage
Solution Approach 1:
The patent segments the printing process into two distinct stages: a first printing unit that applies material to an intermediate substrate, and a second printing unit that transfers material from the intermediate substrate to the final substrate. This segmentation allows each unit to be optimized independently, with the first unit focusing on efficient material application and the second unit focusing on high-precision transfer, thereby resolving the contradiction between manufacturing simplicity and deposition accuracy.
Solution Approach 2:
The patent introduces an intermediate substrate as a mediator between the printing process and the final substrate. This intermediate substrate receives the viscous material in the first printing unit and then transfers it in the second printing unit. The intermediary approach enables better control over material application and transfer, improving manufacturing precision while maintaining process simplicity through modular design.
2Productivity
If printing speed is increased to improve productivity, then output increases, but manufacturing precision deteriorates due to insufficient solder paste application time
Solution Approach 1:
By dividing the printing process into two separate units operating at different speeds and functions, the system allows the first printing unit to operate at high speed for productivity while the second printing unit operates at optimized speed for precision transfer. The intermediate substrate acts as a buffer that decouples the speed requirements of material application from material transfer, enabling high overall productivity without sacrificing application quality.
3Manufacturing precision
If jet printing is used for high precision solder paste application, then manufacturing precision improves, but device complexity increases due to clogging issues with highly viscous materials
Solution Approach 1:
The intermediate substrate serves as a mediator that receives viscous material through a simplified first printing process and then enables precise transfer through a second printing process. This approach avoids the need for complex jetting systems to directly handle highly viscous solder paste, as the intermediate substrate facilitates the transfer process with reduced clogging risks and lower device complexity.
Solution Approach 2:
The patent replaces direct mechanical jetting of highly viscous materials with a transfer-based system using an intermediate substrate. This substitution eliminates the clogging issues inherent in direct jetting of viscous materials while maintaining high precision through controlled transfer, thereby reducing device complexity.
4Device complexity
If a single printing unit is used, then device complexity is low, but manufacturing precision deteriorates due to inability to achieve high resolution with viscous materials
Solution Approach 1:
The patent divides the printing system into two specialized printing units: the first unit optimized for applying viscous material to the intermediate substrate, and the second unit optimized for high-resolution transfer to the final substrate. This segmentation enables high manufacturing precision through specialized functionality in each unit while keeping individual unit complexity manageable, resolving the contradiction between device complexity and printing resolution.
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 allows for high-speed, high-resolution printing of viscous materials like solder paste with reduced defects and waste, enabling more precise control over solder application and extending the pot life of the material by maintaining a controlled environment.
Implementation Method 1
a laser-assisted deposition system
Implementation Method 2
a laser-assisted deposition system
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
Systems and methods in which dot-like portions of a material (e.g., a viscous material such as a solder paste) are printed or otherwise transferred onto an intermediate substrate at a first printing unit, the intermediate substrate having the dot-like portions of material printed thereon is transferred to a second printing unit, and the dot-like portions of material are transferred from the intermediate substrate to a final substrate at the second printing unit. Optionally, the first printing unit includes a coating system that creates a uniform layer of the material on a donor substrate, and the material is transferred in the individual dot-like portions from the donor substrate onto the intermediate substrate at the first printing unit. Each of the first and second printing units may employ a variety of printing or other transfer technologies. The system may also include material curing and imaging units to aid in the overall process.