Zone Heater Gas Deflector for Uniform Reflow Solder Heating
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Solution Overview
Problem
Variation in gas flow and temperature uniformity in reflow soldering tools leads to hot spots and cold spots, reducing throughput and quality of solder joints, resulting in increased failure rates and reduced yield of semiconductor device packages.
Innovation Solution
Incorporation of a gas deflector with a single-layer structure and gas-permeating patterns in the zone heater assembly to promote uniform gas flow and temperature distribution across the heating zone, ensuring consistent convection heat for solder reflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heating zones are used without gas deflectors, then the structure is simpler, but gas flow and temperature distribution are non-uniform causing hot spots
Solution Approach 1:
A gas deflector is introduced as an intermediary component between the heating elements and the substrate. This deflector mediates the heat transfer by directing gas flow patterns, ensuring uniform temperature distribution across the substrate surface while preventing direct thermal contact and hot spots.
Solution Approach 2:
The heating zone is designed with spatially varying properties - the gas deflector creates localized flow patterns with different velocities and directions in different regions. This local quality variation ensures that each area of the substrate receives appropriate heat distribution, preventing uniform overheating while maintaining overall temperature uniformity.
2Productivity
If substrate placement flexibility is increased to improve throughput, then productivity increases, but temperature control uniformity deteriorates
Solution Approach 1:
The gas deflector design creates equipotential temperature zones across the heating area. By carefully designing the gas flow patterns, the system ensures that all regions of the substrate experience equivalent thermal conditions, allowing substrates to be placed in various positions while maintaining uniform temperature control and consistent soldering quality.
3Loss of time
If gas flow velocity is increased to reduce processing time, then productivity improves, but temperature uniformity deteriorates causing hot spots
Solution Approach 1:
The gas deflector system employs dynamic flow control with multiple gas inlets that can be independently adjusted. This allows the system to adapt gas flow velocities in real-time based on processing requirements, maintaining optimal temperature uniformity while achieving reduced processing times through coordinated multi-zone flow management.
Solution Approach 2:
The heating zone is segmented into multiple independent gas flow zones, each controlled by separate gas inlets. This segmentation allows different regions to operate at different gas flow rates simultaneously, enabling fast processing in critical areas while maintaining temperature uniformity in other regions, thus preventing hot spots even at high overall processing speeds.
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
Enhances productivity by allowing more semiconductor packages to be processed per hour with higher-quality solder joints, reducing failure rates and increasing yield.
Implementation Method 1
Each heating zone is configured to provide convection heat onto the semiconductor package substrates at a particular temperature
Implementation Method 2
The zone heater assembly is used to generate the process gas by heating one or more inlet gasses
Data Source
AI summary
A zone heater assembly of a reflow solder tool includes a gas deflector having a single-layer structure. The single-layer structure may include one or more gas-permeating patterns through which a process gas is to flow from one or more gas outlets to a gas exhaust of the zone heater assembly. The one or more gas-permeating patterns in the single-layer structure promote uniformity of gas flow through the gas exhaust and into a heating zone of the reflow solder tool. The uniformity of the gas flow of the process gas enables convection heat provided by the process gas to be uniformly distributed across the heating zone. In this way, the gas deflector described herein may decrease hot spots and/or cold spots in the heating zone, which enables greater flexibility in placement of semiconductor package substrates on a conveyor device of the reflow solder tool.