Sacrificial Interposer Test Structure for Single-Sided Electrical Testing
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Solution Overview
Problem
The challenge lies in testing the electrical connections of interposers, particularly those with ultra-high density circuitry, as flaws can render devices inoperable due to open or shorted connections, and existing methods struggle to access buried interconnects on one side of the interposer, leading to potential faulty chip packages and waste.
Innovation Solution
A sacrificial interposer test structure is created with a release layer, dummy layer, conductive pads, and a tie layer, allowing electrical testing from a single surface by forming conductive paths that can be measured for defects, enabling identification of open or shorted connections without requiring access to the opposite side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional testing methods are used to access buried interconnects, then both sides of the interposer must be accessible, but this increases device complexity and production waste due to inability to test single-sided configurations
Solution Approach 1:
A sacrificial test structure is introduced as an intermediary element that provides temporary access to buried interconnects during testing. This sacrificial structure includes conductive pads and tie layers that enable electrical connection to otherwise inaccessible interconnects, allowing complete testing from a single side without requiring access to both sides of the interposer
Solution Approach 2:
The test structure is segmented into distinct functional layers: a sacrificial layer that provides initial access, conductive pads for electrical connection, and tie layers that connect the pads to the interconnects. This segmentation allows each component to perform its specific function while enabling complete testing capability
2Reliability
If both sides of the interposer are made accessible for testing, then all interconnects can be tested, but this increases manufacturing complexity and cost
Solution Approach 1:
The sacrificial test structure is formed preliminarily during the interposer fabrication process, before the interposer is completed and packaged. The conductive pads and tie layers are created in advance, allowing testing to be performed early in the manufacturing flow without requiring complex post-processing or dual-sided access modifications
Solution Approach 2:
The sacrificial structure serves as a temporary intermediary that enables testing without requiring permanent modifications to the interposer design or dual-sided accessibility, simplifying the overall manufacturing process
3Productivity
If testing is performed without a sacrificial structure, then the process is simpler, but defects cannot be detected early leading to production waste
Solution Approach 1:
Testing is performed preliminarily using the sacrificial structure before the interposer is finalized and packaged. This early detection capability identifies defective interposers before they proceed through subsequent manufacturing steps, preventing waste of materials and processing time on faulty devices
Solution Approach 2:
The sacrificial test structure provides a protective testing mechanism that identifies defects beforehand, cushioning against the production of faulty devices by enabling early rejection of defective interposers before they consume additional manufacturing resources
Data Source
AI summary
A sacrificial interposer test structure including a release layer, a dummy layer on the release layer, one or more conductive pads embedded in the dummy layer, wherein each of the one or more conductive pads has an exposed surface, and a tie layer on the dummy layer and on each exposed surface of the one or more conductive pads.