Separately Controlled Plates for Warpage-Compensated Ball Placement
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Solution Overview
Problem
Semiconductor packages experience warpage due to differences in thermal expansion coefficients between the PCB and encapsulant, leading to improper attachment of conductive balls, resulting in defects such as missing, extra, or misplaced balls during the attachment process.
Innovation Solution
A device comprising first and second plates with recesses for suctioning and dropping conductive balls, and a controller to adjust the position of these plates based on substrate warpage, ensuring accurate placement by reducing deviations in gap distances between the plates and the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single plate is used for attaching conductive balls, then the device structure is simple, but the placement precision deteriorates due to substrate warpage causing gap deviations
Solution Approach 1:
The single plate is divided into multiple separate plates (first plate and second plate), each independently controllable. This segmentation allows each plate to be positioned at different heights to compensate for substrate warpage, thereby maintaining placement precision without excessive overall device complexity
Solution Approach 2:
The plates are made dynamically adjustable through independent height control mechanisms. Each plate can be moved to different positions based on the local warpage characteristics of the substrate, enabling the system to adapt to varying gap deviations across different regions of the substrate
2Ease of operation
If plates are positioned at the same level, then the device operation is simple, but the attachment reliability deteriorates due to warpage causing improper ball disposal
Solution Approach 1:
The plates transition from a static same-level configuration to a dynamic adjustable configuration. Each plate can be independently positioned to match the local substrate height, ensuring reliable conductive ball attachment despite warpage. The control system automates this adjustment, maintaining ease of operation while improving reliability
Solution Approach 2:
Each plate is given the capability to be positioned at a different height suitable for its specific region of the substrate. This local quality adjustment ensures that each plate makes optimal contact with its corresponding substrate area, improving attachment reliability without requiring complex global repositioning
3Manufacturing precision
If multiple separately controlled plates are used, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The system is segmented into multiple independently controllable plates, each responsible for a specific region of the substrate. This segmentation improves placement precision by allowing localized height adjustment. The modular nature of the segmentation helps manage device complexity through standardized, repeatable units
Solution Approach 2:
Each plate serves multiple functions: it holds conductive balls, positions them precisely, and can be independently height-adjusted to compensate for warpage. This multi-functionality reduces the need for additional specialized components, thereby improving precision without proportionally increasing overall device complexity
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
The device effectively reduces defects in conductive ball attachment by ensuring precise placement on substrate pads, enhancing manufacturing productivity and reducing manual corrections or substrate discarding.
Implementation Method 1
Each recess is configured to suction one of the conductive balls
Data Source
AI summary
A device for attaching conductive balls to a substrate includes a first plate, a second plate and a controller. The first plate includes first recesses. Each of the first recesses picks up a corresponding conductive ball to be attached to the semiconductor package. The second plate includes second recesses. Each of the second recesses picks up a corresponding conductive ball to be attached to the semiconductor package. The first plate and the second plate are separated from each other. The controller controls each of the first plate and the second plate to be separately moved up or down so that a lower surface of the first plate and a lower surface of the second plate are positioned differently in a first direction normal the lower surface of the first plate.