Metal Stopper Bump Die Leveling for IC Tilt Control
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Solution Overview
Problem
The challenge in modern integrated chip (IC) packaging is the tilting of semiconductor dies due to variability in adhesive viscosity, manipulation, dispensing, shrinkage, and geometry, leading to performance issues and increased manufacturing costs, particularly in devices with accelerometers and optical components.
Innovation Solution
The introduction of stopper bumps, in addition to an adhesive structure, between the semiconductor die and the substrate or package, to constrain the gap and control the angle of the die, ensuring proper alignment and leveling, thereby reducing tilt and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive structure alone is used to attach semiconductor die to substrate, then manufacturing process is simple, but die tilting occurs due to variability in adhesive viscosity, dispensing, and shrinkage
Solution Approach 1:
Metal stopper bumps are introduced as intermediary elements between the adhesive structure and the semiconductor die. These stopper bumps serve as mechanical spacers that prevent the die from tilting by providing a physical barrier at predetermined locations, thereby ensuring precise die alignment while maintaining manufacturing simplicity
Solution Approach 2:
The invention changes the physical parameters of the attachment system by adding metal stopper bumps with specific heights and locations. These parameter changes (height, location, material composition) allow control over die positioning and tilt prevention, transforming the attachment mechanism from relying solely on adhesive properties to a combined mechanical-adhesive system
2Manufacturing precision
If adhesive viscosity and geometry are controlled to prevent die tilting, then die alignment improves, but manufacturing complexity and costs increase
Solution Approach 1:
Metal stopper bumps serve as intermediary mechanical elements that simplify the manufacturing process by providing a straightforward physical constraint mechanism. Instead of requiring complex adhesive formulation and dispensing control, the stopper bumps provide intuitive geometric constraints that are easier to manufacture and inspect
Solution Approach 2:
The attachment system is segmented into distinct functional components: the adhesive structure for bonding and the metal stopper bumps for mechanical positioning and tilt prevention. This segmentation allows each component to be optimized independently, reducing overall manufacturing complexity while maintaining high precision
3Productivity
If die tilting is not controlled, then manufacturing process remains fast and simple, but device performance deteriorates and post-packaging calibration is required
Solution Approach 1:
Metal stopper bumps are pre-positioned on the substrate before die attachment. This preliminary action establishes the mechanical constraints needed for proper die leveling, ensuring that when the die is attached using the adhesive structure, it automatically achieves the correct orientation without requiring post-packaging calibration
Solution Approach 2:
The metal stopper bumps act as intermediary elements that transfer the positioning information from the substrate to the die during attachment. They mediate the interaction between adhesive and die, ensuring that the die is positioned correctly while maintaining fast and simple manufacturing processes
Data Source
AI summary
In some embodiments, the present disclosure relates to an integrated chip (IC), including a substrate, a first die disposed over the substrate, a metal wire attached to a frontside of the first die, and a first plurality of die stopper bumps disposed along a backside of the first die and configured to control an angle of operation of the first die. The first plurality of die stopper bumps directly contacts a backside surface of the first die.