Underfill Dispensing With Zoned Heating for Uneven Bump Density
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Solution Overview
Problem
In semiconductor manufacturing, uneven bump density leads to inconsistent underfill flow, causing productivity issues and void formation due to either slow flow in high-density areas or rapid flow in low-density areas, affecting the quality and reliability of semiconductor devices.
Innovation Solution
An underfill dispensing system with a heating structure composed of multiple heating blocks that can be independently controlled based on imaging and machine learning, applying targeted heating to adjust underfill viscosity according to bump density patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform heating is applied across all bonding areas, then the underfill dispensing process is simple to control, but the underfill flow becomes inconsistent in areas with varying bump density
Solution Approach 1:
The heating structure is divided into multiple independently controllable heating blocks corresponding to different bonding areas. Each heating block can be controlled separately based on the bump density of its corresponding bonding area, allowing precise temperature management for uniform underfill flow across the entire substrate.
Solution Approach 2:
Different heating blocks are assigned different temperature characteristics matched to the bump density of their corresponding bonding areas. High-density areas receive heating blocks with temperature characteristics that accelerate underfill flow, while low-density areas receive heating blocks that prevent void formation, achieving locally optimized underfill distribution.
2Productivity
If heating temperature is increased to accelerate underfill flow, then productivity improves, but voids may form in low-density areas where flow becomes too rapid
Solution Approach 1:
The heating structure is segmented into multiple heating blocks that can be independently controlled. This allows different temperature levels to be applied to different bonding areas simultaneously, enabling fast flow in high-density areas while maintaining controlled flow in low-density areas to prevent voids.
Solution Approach 2:
The temperature parameter of each heating block is adjusted according to the bump density of its corresponding bonding area. By changing the temperature parameter locally rather than uniformly, the system achieves both high productivity in dense areas and high reliability in sparse areas.
3Manufacturing precision
If multiple independently controlled heating blocks are used to achieve uniform underfill distribution, then underfill flow consistency improves, but the control system complexity increases
Solution Approach 1:
The heating structure is divided into multiple heating blocks, each corresponding to a specific bonding area. This segmentation allows the control system to manage each area independently based on its bump density characteristics, achieving uniform underfill distribution across the entire substrate despite the increased number of control elements.
Solution Approach 2:
Each heating block is assigned specific temperature characteristics tailored to its corresponding bonding area's bump density. This local customization of heating properties enables precise control of underfill flow in each area, achieving overall uniformity through localized optimization.
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
Ensures uniform underfill distribution by accelerating flow in high-density areas and preventing voids in low-density areas, enhancing the efficiency and quality of semiconductor assembly.
Implementation Method 1
The heating structure is disposed on an upper surface of the substrate table and includes a plurality of heating blocks
Implementation Method 2
This underfill is drawn into the small gap between the chip and the substrate by capillary action
Data Source
AI summary
An underfill dispensing system includes a substrate table configured to support a substrate including a plurality of bonding areas for mounting a plurality of semiconductor chips, a heating structure disposed on an upper surface of the substrate table and including a plurality of heating blocks, a dispensing head configured to dispense underfill to a plurality of bonding areas of the substrate, above the substrate table, an imaging device, and a control unit configured to control the heating structure and the dispensing head. The imaging device is configured to image at least one of the substrate and the plurality of semiconductor chips to generate an image. The controller is configured to control the plurality of heating blocks independently of one another based on the image.