Compressive Insulating Film Recess for Semiconductor Stress Relief
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Solution Overview
Problem
In semiconductor devices, insulating films between or on wirings can experience stress-related issues like peeling, floating, and cracking, affecting yield and quality due to adhesion deterioration and instability in film formation.
Innovation Solution
A compressive insulating film with a recess in its central portion is formed, reducing thickness and stress, thereby stabilizing the film and preventing peeling, floating, and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the insulating film is formed with uniform thickness, then the film coverage is improved, but stress concentration causes peeling and cracking
Solution Approach 1:
The insulating film is designed with varying thickness: thicker at edges for coverage and thinner at center for stress relief. This local quality variation allows the film to maintain both broad coverage and structural integrity by adapting thickness to functional requirements at different locations.
Solution Approach 2:
A recess is formed in the central portion of the insulating film before subsequent wiring formation. This preliminary structural modification prevents stress concentration from causing peeling and cracking in later processing steps, proactively addressing the reliability issue.
2Reliability
If the insulating film thickness is increased, then the insulation performance is improved, but stress-induced peeling and floating occur
Solution Approach 1:
The insulating film employs non-uniform thickness distribution: sufficient thickness at edges for insulation while reduced thickness at center minimizes stress accumulation. This resolves the contradiction between maintaining insulation performance and preventing stress-induced adhesion failure.
Solution Approach 2:
Instead of uniformly increasing thickness throughout, the invention applies thickness increase only where needed (edges for insulation) while maintaining reduced thickness where it causes problems (center for stress). This partial application of thickness enhancement achieves insulation without excessive stress.
3Reliability
If a stress relaxation layer is inserted, then film peeling is prevented, but device complexity increases
Solution Approach 1:
The insulating film is segmented into regions of different thickness rather than adding a separate relaxation layer. The central recess creates a thin-film region that acts as a stress relaxation zone, achieving film stability through internal segmentation rather than external additive structures.
Solution Approach 2:
Material is removed from the central portion of the insulating film to create a recess, rather than adding a separate relaxation layer. This extraction approach reduces stress concentration while avoiding the complexity of multi-layer structures, achieving film stability through subtraction rather than addition.
Data Source
AI summary
An insulating film (2) is provided on a base material (1). The insulating film (2) is a compressive film in which a stress is applied in a direction of peeling away from the base material at a central portion. A recess (3) is formed in the central portion of the insulating film (2) so that a thickness is partially reduced.