Multi-layer Substrate with Embedded Bond Pad Layer for Flatness
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Solution Overview
Problem
The existing multi-layer substrate manufacturing methods, such as Sequential Lamination and Build-up methods, result in a surface dielectric layer that is significantly thicker than the bond pad and metal layers, leading to poor flatness, which becomes critical with increased integration of integrated circuits, affecting the reliability and yield of Flip-Chip and other high integration packages.
Innovation Solution
A method where the bond pad layer is embedded within the surface dielectric layer, ensuring coplanarity and improved flatness, achieved by forming the bond pad layer on a flat carrier surface and then embedding it within the surface dielectric layer, followed by separation from the carrier, allowing for precise alignment and bonding in high integration packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface dielectric layer is made thicker to provide sufficient dielectric strength, then the electrical insulation performance is improved, but the flatness of the bond pad layer deteriorates
Solution Approach 1:
The invention transitions from a conventional planar stacking arrangement to a three-dimensional embedded structure where the bond pad layer is partially embedded in the surface dielectric layer. This dimensional change allows the dielectric layer to provide sufficient thickness for electrical insulation while the bond pad layer maintains its lateral extent for electrical connection, resolving the contradiction between dielectric strength and flatness.
Solution Approach 2:
The bond pad layer is nested within the surface dielectric layer, with portions of the bond pad layer embedded in the dielectric material. This nesting arrangement allows the dielectric layer to surround and protect the conductive elements while maintaining a relatively flat top surface, simultaneously achieving electrical insulation and surface flatness.
2Manufacturing precision
If the thickness of the surface dielectric layer is reduced to improve flatness, then the manufacturing precision is improved, but the electrical insulation performance deteriorates
Solution Approach 1:
The surface dielectric layer exhibits local quality variations: it is thicker in regions where electrical insulation is critical (away from bond pads) and thinner or recessed in regions where bond pad embedding occurs. This localized thickness variation allows the overall layer to provide sufficient dielectric strength while maintaining a flat top surface for packaging applications.
3Device complexity
If the thickness of bond pad layer and metal layer is reduced to increase integration, then the device complexity is reduced, but the electrical performance deteriorates
Solution Approach 1:
The invention uses a composite structure combining the bond pad layer (conductive material) with the surface dielectric layer (insulating material) in an embedded arrangement. This composite structure provides both the electrical connection function of the bond pad and the insulation function of the dielectric layer, allowing for reduced individual layer thicknesses while maintaining overall electrical performance and enabling higher integration.
Data Source
AI summary
Disclosed are a multi-layer substrate and a manufacture method thereof. The multi-layer substrate of the present invention comprises a surface dielectric layer and at least one bond pad layer. The surface dielectric layer is located at a surface of the multi-layer substrate. The bond pad layer is embedded in the surface dielectric layer to construct the multi-layer substrate with the surface dielectric layer of the present invention. The manufacture method of the present invention forms at least one bond pad layer on a flat surface of a carrier and then forms the surface dielectric layer to cover the bond pad layer where the bond pad layer is embedded therein. After the multi-layer substrate is separated from the carrier, the bond pad layer and the surface dielectric layer construct a flat surface of the multi-layer substrate.