Lateral coupling for topside dual-side testing of TSV die
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Solution Overview
Problem
The existing methods for testing stacked electronic assemblies, particularly those with Through Substrate Vias (TSV) in PoP (Package on Package) configurations, face challenges in detecting electrical issues like TSV formation problems, contact problems, and shorts due to the presence of a carrier that blocks access to the TSV die, leading to shipment of defective thinned PoP precursors and subsequent failures at final testing.
Innovation Solution
A method for topside dual-side testing of TSV die, where a singulated TSV die is flip chip attached to a multi-layer package substrate with lateral coupling paths between embedded topside substrate pads and lateral topside pads, allowing contact and testing of TSV tips from the topside, even when a substrate carrier is present, using probes to establish connections and test parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a substrate carrier is used to provide rigidity during assembly, then structural stability is improved, but access to the TSV die bottom side is blocked preventing electrical testing
Solution Approach 1:
The substrate is divided into two functional layers: a substrate carrier that provides structural stability and rigidity, and a separate package substrate that enables electrical access. This segmentation allows the carrier to maintain structural integrity while the package substrate provides pathways for testing TSV connections from the topside.
Solution Approach 2:
The package substrate acts as an intermediary between the TSV die and the testing equipment. It provides lateral coupling paths that route electrical signals from the topside contact pads, through the package substrate, to the TSV connections, enabling testing without direct access to the die bottom side.
2Productivity
If probing after die attach is omitted to save time, then manufacturing productivity is improved, but defective assemblies are shipped resulting in quality deterioration
Solution Approach 1:
Electrical testing is performed at an intermediate stage during assembly rather than waiting until final product completion. The testing capability is built into the assembly process itself, allowing defects to be detected and corrected before final shipping, thus maintaining both productivity and quality.
3Ease of operation
If TSV die are thinned to expose TSV tips for contact, then electrical contact capability is improved, but detection of TSV formation problems and contact issues becomes more difficult due to carrier presence
Solution Approach 1:
The testing approach transitions from vertical access (bottom side probing) to lateral access through the package substrate. By routing test signals laterally through the package substrate's coupling paths, the system enables detection of TSV defects without requiring direct vertical access to the TSV tips, thus solving the detection difficulty while maintaining contact capability.
Data Source
AI summary
A method of topside only dual-side testing of an electronic assembly includes providing a singulated through substrate via (TSV) die flip chip attached to a die support including a package substrate. The TSVs on the TSV die extend from its frontside to contactable TSV tips on its bottomside. The TSVs on the frontside of the TSV die are coupled to embedded topside substrate pads on a top surface of the ML substrate. The die support includes lateral coupling paths between at least a portion of the embedded topside substrate pads and lateral topside pads on a topside surface of the die support lateral to the die area. The contactable TSV tips are contacted with probes to provide a first topside connection to the TSVs, and the lateral topside pads are contacted with probes to provide a second topside connection. Dual-side testing across the electronic assembly is performed using the first and second topside connections.