Monolithic Conductive Columns for Stacked Die Vertical Interconnects
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Solution Overview
Problem
The challenge in semiconductor devices is the ineffective bonding and limited electrical conductivity between stacked semiconductor dies due to issues with conductive columns, such as underfilling or overfilling, which leads to structural and performance problems, including concave recesses, convex protrusions, and material-property-based limitations on electricity transfer.
Innovation Solution
The implementation of monolithic conductive columns that extend through both semiconductor dies and molding material, eliminating the need for additional conductive material between dies and allowing for wider conductive paths through the molding material, thereby improving bonding and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional conductive columns are used in stacked semiconductor dies, then the bonding process can be simplified, but the bonding effectiveness deteriorates due to underfilling or overfilling causing concave recesses or convex protrusions
Solution Approach 1:
The patent applies preliminary action by pre-forming the conductive column with a controlled convex protrusion at its top surface before the bonding process. This pre-shaping compensates for the expected material settling and concave formation during bonding, ensuring that the protrusion becomes a flat surface after bonding, thereby maintaining effective bonding area and electrical contact.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the height and dimensions of the conductive column's top surface to create a convex protrusion. This geometric parameter modification ensures that after bonding and material settling, the final surface is substantially flat, optimizing both bonding effectiveness and electrical conductivity without requiring complex bonding process adjustments.
2Volume of moving object
If conductive column size is reduced to save space in stacked semiconductor dies, then the volume occupied is reduced, but the electrical conductivity deteriorates due to material property constraints
Solution Approach 1:
The patent applies dimensionality change by extending the conductive column vertically through the molding material beyond the die surface, creating a through-substrate via structure. This vertical extension provides an additional dimensional pathway for electrical conduction, compensating for the reduced cross-sectional area of the column within the die, thereby maintaining electrical conductivity while minimizing space occupation within the die volume.
Solution Approach 2:
The patent employs composite materials by forming the conductive column from conductive material and combining it with molding material that fills the remaining space in the via. This composite structure allows the conductive column to maintain small dimensions within the die while the external protrusion provides sufficient conductive pathway length, and the molding material provides structural support and insulation.
3Volume of stationary object
If bond line thickness is reduced to decrease assembly volume, then the overall device size is reduced, but the structural integrity deteriorates causing ineffective bonding and die separation
Solution Approach 1:
The patent applies preliminary action by pre-forming the conductive column with a convex protrusion that extends beyond the die surface before bonding. This pre-positioned protrusion ensures that even with reduced bond line thickness, the conductive material maintains adequate contact area with adjacent dies, preventing die separation and maintaining bonding strength while allowing thinner bond lines for compact assembly.
4Ease of manufacture
If conventional conductive columns are used with additional conductive material for bonding, then the bonding process is straightforward, but the manufacturing precision deteriorates due to difficulty in controlling underfilling or overfilling
Solution Approach 1:
The patent applies the extraction principle by removing the need for additional conductive material filling operations. The conductive column itself is pre-formed with the necessary protrusion structure that serves both as the conductive pathway and as the bonding interface, eliminating the separate step of adding and controlling additional conductive material fill, thereby improving manufacturing precision.
Data Source
AI summary
A semiconductor device having monolithic conductive columns, and associated systems and methods, are disclosed herein. The semiconductor device can include a semiconductor die and a molding material. The semiconductor die may have a semiconductor substrate, a conductive pad, an opening, a non-conductive liner, and a plug of non-conductive material. The conductive pad may be at a surface of the semiconductor substrate. The opening may extend through the semiconductor substrate from the conductive pad to a second surface and define a side wall. The liner may coat the side wall and the plug may fill the opening. A second opening may be formed through the semiconductor device and the opening and a conductive material plated therein. The molding material may be laterally adjacent to the semiconductor die.