Passivation Layer Planarization for Stress-Resistant 3D Memory
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Solution Overview
Problem
Conventional 3D semiconductor die assemblies face challenges in stress distribution and passivation material integrity due to uneven topography and random misalignment of pillars, leading to cracking and compromised integrity.
Innovation Solution
A microelectronic device design featuring a thicker second passivation material with patterned upper regions to provide a flat surface and support structural elements, distributing stress and reducing the risk of cracking by increasing the effective surface area for structural elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pillars are placed on an uneven topography of passivation material, then electrical connection is achieved, but stress distribution deteriorates causing cracking
Solution Approach 1:
The patent applies preliminary action by forming a planarization layer before placing the pillars. This layer pre-compensates for the uneven topography, ensuring that when pillars are subsequently placed, they rest on a flat surface that distributes stress uniformly. The planarization layer is formed in advance to create a uniform stress distribution surface, preventing cracking before it occurs.
Solution Approach 2:
The patent introduces an intermediary planarization layer between the uneven passivation material and the pillars. This intermediary layer acts as a mediator that transforms the uneven surface into a flat surface, allowing pillars to be placed without direct contact with the irregular topography, thereby distributing stress evenly and preventing cracks in the passivation material.
2Object-affected harmful factors
If passivation material conforms to uneven metallization topography, then environmental protection is provided, but stress resistance deteriorates
Solution Approach 1:
The planarization layer is formed preliminarily before placing structural elements on the passivation material. This preliminary action creates a flat surface that distributes stress uniformly, preventing cracks while maintaining the environmental protection function of the passivation material.
Solution Approach 2:
The planarization layer serves as an intermediary between the uneven metallization structures and the passivation material. It allows the passivation material to conform to a flat surface rather than the uneven topography, maintaining its protective function while improving stress resistance.
3Ease of manufacture
If pillars are randomly misaligned with underlying structures, then manufacturing simplicity is maintained, but stress distribution worsens causing stress points
Solution Approach 1:
The planarization layer acts as an intermediary that decouples the positioning of pillars from the underlying uneven structures. Pillars can be placed on the flat surface of the planarization layer without precise alignment requirements, while the layer itself ensures uniform stress distribution to the underlying structures, eliminating stress points caused by misalignment.
Solution Approach 2:
The planarization layer is formed in advance to create a uniform surface. This preliminary action allows pillars to be placed with greater flexibility without causing stress concentration, as the layer pre-distributes the stress uniformly across the underlying structures regardless of pillar alignment.
4Length of moving object
If thin passivation material is used, then device thickness is reduced, but cracking resistance deteriorates
Solution Approach 1:
The planarization layer is formed preliminarily to create a flat surface that distributes stress uniformly. This allows the use of thinner passivation material while maintaining cracking resistance, as the stress distribution function is provided by the planarization layer rather than relying solely on the thickness of the passivation material.
Data Source
AI summary
An apparatus comprises conductive segments comprising an uneven topography comprising upper surfaces of the conductive segments protruding above an upper surface of underlying materials, a first passivation material substantially conformally overlying the conductive segments, and a second passivation material overlying the first passivation material. The second passivation material is relatively thicker than the first passivation material. The apparatus also comprises structural elements overlying the second passivation material. The second passivation material has a thickness sufficient to provide a substantially flat surface above the uneven topography of the underlying conductive segments at least in regions supporting the structural elements. Microelectronic devices, memory devices, and related methods are also disclosed.