Ball-Height Control Studs for Standoff Distance in Bonded Packages
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Solution Overview
Problem
The increased integration of applications in packaging leads to warpage and CTE mismatch issues, causing variations in standoff distance between bonded package components, which results in reliability problems due to the dramatic increase in electrical connectors like solder balls.
Innovation Solution
The implementation of ball-height control studs during the bonding process, which are strategically placed between the package components to control the standoff distance by selecting their height to be between (W1−80 μm) and about W1, thereby stabilizing the bonding process and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of solder balls is increased to meet increased integration requirements, then the integration level is improved, but warpage and CTE mismatch cause variation in standoff distance resulting in reliability problems
Solution Approach 1:
Ball-height control studs are introduced as intermediary elements between the package substrate and PCB to mediate the standoff distance control. These studs act as mechanical mediators that compensate for warpage and CTE mismatch effects, maintaining reliable electrical connections despite substrate deformation caused by increased solder ball count and integration density.
Solution Approach 2:
The patent changes the physical parameter of standoff distance by introducing ball-height control studs with specific heights. This parameter adjustment compensates for variations caused by warpage and CTE mismatch, allowing the system to maintain optimal electrical connection geometry even as integration level and solder ball count increase.
2Quantity of substance
If more solder balls are used to increase integration, then the number of electrical connectors increases, but warpage and CTE mismatch cause variation in standoff distance
Solution Approach 1:
Ball-height control studs serve as intermediary reference structures that decouple the standoff distance control from the substrate warpage. By providing fixed-height reference points, these studs enable precise solder ball placement and consistent electrical connection geometry even when using large numbers of solder balls across warpright substrates.
Solution Approach 2:
The patent introduces a new controllable parameter (stud height) that directly determines standoff distance. This parameter can be precisely controlled during manufacturing to compensate for warpage effects, enabling consistent manufacturing precision regardless of the number of solder balls used for high integration.
3Reliability
If ball-height control studs are used to control standoff distance, then reliability is improved, but device complexity increases
Solution Approach 1:
The ball-height control stud structure is segmented into distinct functional portions: a body portion that provides mechanical support and a head portion that defines the standoff distance reference. This segmentation allows each portion to be optimized independently and simplifies the manufacturing process by enabling separate formation of different functional elements.
Solution Approach 2:
The ball-height control studs are designed to be self-aligning and self-defining during the bonding process. The studs automatically establish the correct standoff distance through their fixed height, eliminating the need for complex external alignment mechanisms or additional control systems, thereby improving reliability without proportionally increasing device complexity.
Data Source
AI summary
A package includes a first package component, a second package component over the first package component, and a solder region bonding the first package component to the second package component. At least one ball-height control stud separates the first package component and the second package component from each other, and defines a standoff distance between the first package component and the second package component.