Semiconductor Landing Pad Design for TSV Connection Reliability
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Solution Overview
Problem
The existing technique for forming a thick TSV landing pad in semiconductor devices is prone to connection failure due to the etching process, leading to cavities and poor electrical properties between the TSV and the landing pad, which compromises reliability.
Innovation Solution
A semiconductor device design that includes a substrate with distinct regions for forming a first metal wiring line and a landing pad, where the landing pad is embedded in the first interlayer film and penetrates the second interlayer film, and a TSV is formed to connect to the landing pad from the backside, ensuring a thicker landing pad without etching damage and maintaining favorable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two or more metal films are stacked to form a thick TSV landing pad, then the thickness of the landing pad is increased to prevent TSV penetration, but the first metal film is affected by etching steps and cavities are formed, leading to poor electric connection
Solution Approach 1:
The patent divides the landing pad formation into separate stages: first forming the landing pad structure, then adding subsequent metal films for wiring. This segmentation prevents the landing pad from being damaged by etching steps intended for other metal layers, thereby maintaining both sufficient thickness and connection reliability.
Solution Approach 2:
The landing pad is formed in advance before the etching steps for subsequent metal films. This preliminary action ensures that the landing pad is already in place and protected, preventing cavities from forming during later etching processes while maintaining adequate thickness to prevent TSV penetration.
2Manufacturing precision
If the first metal film is subjected to etching steps for forming subsequent metal films, then the landing pad thickness is maintained, but the affected portion is washed away causing cavities
Solution Approach 1:
The manufacturing process is segmented into distinct phases: landing pad formation phase followed by subsequent metal film formation phase. This segmentation allows the landing pad to be formed with precise thickness control without being exposed to damaging etching steps, while still enabling multi-layer metal structures to be manufactured.
3Reliability
If a thick landing pad is formed to prevent TSV penetration, then TSV penetration is prevented, but connection failure occurs due to cavities formed during etching
Solution Approach 1:
The landing pad is formed preliminarily before any etching steps that could cause damage. This ensures that when the TSV is subsequently formed, the landing pad maintains both its protective thickness and its structural integrity for reliable electrical connection, eliminating cavity formation issues.
Data Source
AI summary
A semiconductor device includes a first interlayer film formed on an upper surface of a substrate, a first metal wiring line, a second interlayer film, a second metal wiring line, a first via electrically connecting the first metal wiring line and the second metal wiring line, a landing pad embedded in an upper portion of the first interlayer film and penetrating the second interlayer film, and a second via penetrating the substrate and the first interlayer film from a back side of the substrate and connected to the landing pad. The lower surface position of the landing pad is different from that of the first metal wiring line.