Conductive Pad Protrusion Design for Semiconductor Package Reliability
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Solution Overview
Problem
Existing semiconductor devices face reliability issues due to foreign substances interfering between conductive bumps and pads, leading to increased contact resistance and potential adhesion failures.
Innovation Solution
A semiconductor device design featuring a through-hole electrode structure with a redistribution layer and conductive pads having a penetrating portion and a protrusion portion, where the central upper surface of the conductive pad is flat and not closer to the substrate than the edge region, ensuring minimal exposure and preventing oxidation, and a method for manufacturing this structure with varying redistribution layer thicknesses and protection layers to maintain uniform height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive pad has a conventional structure without a protrusion portion, then the manufacturing process is simpler, but foreign substances can remain between the conductive pad and bump causing increased contact resistance and adhesion failures
Solution Approach 1:
The conductive pad is designed with a protrusion portion that creates a curved, dome-shaped upper surface. This curvature ensures that the bonding surface is always convex, preventing the formation of voids or pockets where foreign substances could be trapped between the conductive pad and bump during bonding, thereby eliminating adhesion failures and reducing contact resistance.
2Reliability
If the upper surface of the conductive pad protrudes higher than the edge region, then foreign substances are better prevented, but oxidation of the conductive pad increases due to greater exposure
Solution Approach 1:
The conductive pad employs a localized protrusion portion only at the center, while the edge region remains at a lower height. This local quality differentiation ensures that the bonding interface has the necessary convexity to prevent foreign substance entrapment, while the recessed edges minimize the exposed surface area susceptible to oxidation, thus balancing both requirements.
3Adaptability or versatility
If multiple redistribution layers have different thicknesses, then design flexibility is improved, but maintaining uniform upper surface height becomes more difficult
Solution Approach 1:
The conductive pad structure extends into the vertical dimension with a protrusion portion that compensates for variations in redistribution layer thickness. By adjusting the protrusion height, the upper surface of the conductive pad can be brought to a uniform height level across different redistribution layer configurations, maintaining manufacturing precision while preserving design flexibility in the horizontal dimensions.
Data Source
AI summary
A semiconductor device and a method of manufacturing the same, the device including a through-hole electrode structure extending through a substrate; a redistribution layer on the through-hole electrode structure; and a conductive pad, the conductive pad including a penetrating portion extending through the redistribution layer; and a protrusion portion on the penetrating portion, the protrusion portion protruding from an upper surface of the redistribution layer, wherein a central region of an upper surface of the protrusion portion is flat and not closer to the substrate than an edge region of the upper surface of the protrusion portion.