Microelectronic Multi-Film Stack With Organic Stress Buffer Layers
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Solution Overview
Problem
Inorganic multilayer films in microelectronic devices cause stress imbalances and issues like wafer bending or peeling due to dissimilar layer constituents, leading to performance degradation.
Innovation Solution
A microelectronic device design incorporating a semiconductor substrate with a multi-film stack, a refill layer, and a spacer layer, where the refill and spacer layers are organic layers, with specific dimensional ratios and elastic moduli to balance stress and enhance binding, using materials like flourene oligomer and bisphenol A ethoxylate diacrylate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic multilayer film is used to optimize optical performance, then optical performance is improved, but stress imbalance and wafer bending or peeling occur
Solution Approach 1:
An organic refill layer is introduced as an intermediary between the inorganic multi-film stack and the substrate. This refill layer has different stress characteristics than the inorganic layers, serving as a stress buffer that compensates for the stress imbalance caused by the inorganic multilayer film, thereby preventing wafer bending and peeling while maintaining optical performance
Solution Approach 2:
The patent uses a composite structure combining organic and inorganic materials. The organic refill layer (with elastic modulus 1-10 GPa) is combined with the inorganic multi-film stack (with elastic modulus 60-230 GPa) to create a composite layer system. This composite structure balances the overall stress by combining materials with complementary mechanical properties
2Reliability
If layers with dissimilar constituents are stacked, then optical characteristics are optimized, but stress imbalance and peeling occur
Solution Approach 1:
The organic refill layer acts as a mediator between layers with dissimilar constituents. It provides a transition zone that reduces the abrupt interface between materials with vastly different elastic moduli, thereby reducing interfacial stress and improving binding strength between the inorganic multi-film stack and the substrate
Solution Approach 2:
The patent changes the material parameter (elastic modulus) by introducing an organic layer with intermediate properties between the substrate and the inorganic multi-film stack. This parameter transition reduces the shock of material property mismatch, improving interlayer bonding while maintaining the optical characteristics of the inorganic layers
Data Source
AI summary
An microelectronic device includes a semiconductor substrate, at least one sensing element disposed in the semiconductor substrate, at least one multi-film stack disposed on the semiconductor substrate and covering the sensing element, a refill layer disposed on the semiconductor substrate and encircling the multi-film stack, and a spacer layer disposed on the multi-film stack and the refill layer. An area of a top surface of the multi-film stack is less than an area of a bottom surface of the multi-film stack. The multi-film stack has a first dimension measured in a direction, a section of the refill layer has a second dimension measured in the direction, and a ratio of the second dimension to the first dimension is in a range from 0.03 to 0.06. The refill layer and the spacer layer are organic layers.