Bonding Contact Area with Reinforcing Structure for Semiconductor Substrates
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Solution Overview
Problem
Bonding contact areas on semiconductor substrates face mechanical failures such as fracture, deformation, and delamination due to mechanical loading and ultrasonic stresses during the bonding process, especially with the introduction of copper bond wires and advanced metallization processes, leading to reliability issues.
Innovation Solution
A bonding contact area with a reinforcing structure comprising regularly arranged dielectric islands and metal layers, where the reinforcing structure is formed below the bonding surface, and through-connections are placed outside the bonding pad area to enhance mechanical properties and minimize crack formation, using a patterned grid-like structure with offset metal layer edges for improved mechanical and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bonding contact area uses conventional dielectric and metallization layers, then the structure is simple and easy to manufacture, but mechanical loading and ultrasonic stresses during bonding cause fracture, deformation, and delamination
Solution Approach 1:
The bonding contact area is segmented into multiple functional layers: a first metallization layer for electrical connection, a first dielectric layer for insulation, and a second metallization layer forming a bonding pad. This segmentation allows each layer to perform its specific function optimally, improving bonding reliability while maintaining manufacturing feasibility through standardized layer-by-layer fabrication processes.
Solution Approach 2:
The bonding contact area employs a composite structure combining different materials with complementary properties: conductive metals (aluminum, copper, or tungsten) for electrical connectivity, insulating dielectrics (such as silicon dioxide or silicon nitride) for electrical isolation, and adhesion layers (such as titanium nitride or chromium) for enhanced bonding strength. This composite material approach resolves the contradiction by integrating materials that collectively provide both mechanical robustness and electrical functionality.
2Use of energy by moving object
If copper bond wires are used instead of gold bond wires, then energy absorption during bonding increases and operating temperature increases, but mechanical failures intensify
Solution Approach 1:
The invention adapts the bonding contact area structure to accommodate copper bond wires by modifying material parameters and layer configurations. The metallization layers use copper-compatible materials, the dielectric layers are selected for thermal stability at higher operating temperatures, and adhesion layers are optimized for copper bonding. This parameter adaptation allows the structure to handle increased energy absorption and temperature while maintaining reliability.
Solution Approach 2:
The bonding contact area incorporates adhesion layers (such as titanium nitride or chromium) between the copper bond wires and the metallization layers, as well as stress-distribution structures in the dielectric layers. These elements serve as beforehand cushioning measures that prevent mechanical failures by enhancing interfacial bonding strength and distributing thermal and mechanical stresses before they can cause fracture or delamination.
3Reliability
If through-connections are placed inside the bonding pad area, then electrical connection is achieved, but mechanical stress concentration occurs leading to crack formation
Solution Approach 1:
The invention extracts the through-connections from the bonding pad area and relocates them to the surrounding region. The bonding pad maintains its integrity as a continuous conductive layer for mechanical bonding, while separate through-connections in the dielectric layers provide the necessary electrical connectivity to underlying layers. This spatial separation resolves the contradiction by eliminating stress concentration within the bonding pad while preserving electrical functionality.
Data Source
AI summary
A bonding contact area on a semiconductor substrate is provided that includes a reinforcing structure having at least one conductive material layer arranged on the semiconductor substrate to receive the patterned reinforcing structure, a metal layer formed as a bonding contact layer with a bonding surface and arranged on a conductive material layer. Whereby, below the bonding surface, an oxide layer having at least about a 2 μm thickness is arranged, which extends beyond the edge of the bonding surface. The reinforcing structure is arranged in the oxide layer, when viewed looking down onto the bonding surface, outside the bonding surface within the oxide layer.