Conductive Pillar Recesses for Interconnect Continuity Detection
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Solution Overview
Problem
Conventional methods for inspecting the electrical interconnects between semiconductor dies and substrates, such as X-ray imaging, are ineffective in confirming the continuity of conductive pillars and bump material connections, leading to difficulties in detecting interconnect failures.
Innovation Solution
The formation of conductive pillars with recesses or protrusions on semiconductor dies, which allow bump material to flow into or onto these features, indicating electrical continuity and facilitating visual or X-ray inspection for fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional X-ray imaging techniques are used to inspect electrical interconnects, then the inspection process can be performed, but the continuity of conductive pillars and bump material connections cannot be confirmed
Solution Approach 1:
The patent applies the principle of visual differentiation by forming recesses or protrusions on conductive pillars that interact with bump material to create detectable surface features. When bump material fills the recesses or covers the protrusions, it creates a visible indication of electrical continuity that can be detected by inspection systems, effectively translating an internal electrical connection state into an observable external feature.
2Ease of manufacture
If conductive pillars are formed without recesses or protrusions, then the manufacturing process is simpler, but visual or radiographic inspection for fault detection becomes ineffective
Solution Approach 1:
The patent applies preliminary action by pre-forming recesses or protrusions on the conductive pillars during the manufacturing process before the bump material application. This preparatory structuring ensures that when bump material is subsequently applied, it will automatically create a visible indication of continuity, thereby enabling easy inspection without adding complex detection equipment or procedures later in the manufacturing flow.
3Ease of manufacture
If bump material is deposited without conductive pillars having recesses or protrusions, then the deposition process is straightforward, but the presence of bump material cannot be visually confirmed to indicate electrical continuity
Solution Approach 1:
The patent utilizes visual contrast principles where the interaction between bump material and the recesses or protrusions on conductive pillars creates a detectable surface topology. This topographic variation provides visual information about the presence and continuity of electrical interconnects, allowing inspection systems to distinguish between good and bad connections based on surface features created by the bump material's interaction with the pre-formed structures.
Data Source
AI summary
A semiconductor device has a semiconductor die and conductive pillar with a recess or protrusion formed over a surface of the semiconductor die. The conductive pillar is made by forming a patterning layer over the semiconductor die, forming an opening with a recess or protrusion in the patterning layer, depositing conductive material in the opening and recess or protrusion, and removing the patterning layer. A substrate has bump material deposited over a conductive layer formed over a surface of the substrate. The bump material is melted. The semiconductor die is pressed toward the substrate to enable the melted bump material to flow into the recess or over the protrusion if the conductive pillar makes connection to the conductive layer. A presence or absence of the bump material in the recess or protrusion of the conductive pillar is detected by X-ray or visual inspection.