Cu Electrode Bonding Structure With Dummy Pads for Dishing Tolerance
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Solution Overview
Problem
Existing semiconductor bonding methods face challenges in achieving reliable bonding surfaces between Cu electrodes, leading to issues like conduction failures and increased contact resistance due to dishing and misalignment, which affect the bond strength and reliability of the bonding interface.
Innovation Solution
The introduction of dummy electrodes embedded in interlayer insulating films, disposed symmetrically or asymmetrically around the electrode pads, to increase the bonding area and enhance bond strength by intersecting electrode directions, thereby stabilizing the bonding interface even with misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP method is used to planarize bonding surfaces, then flatness of bonding surfaces is improved, but dishing occurs on the bonding surfaces
Solution Approach 1:
The patent applies preliminary anti-action by forming a convex portion on the bonding surface that protrudes from the interlayer insulating film before bonding occurs. This convex structure pre-compensates for the dishing depression that will occur during CMP processing, ensuring that the protruding convex portion makes contact first during bonding, thereby counteracting the harmful effect of dishing and maintaining reliable electrical connection.
2Manufacturing precision
If Cu plates with large area are used for bonding, then misalignment is suppressed, but dishing easily occurs on the bonding surface
Solution Approach 1:
The patent segments the Cu electrode into two functional parts: a large-area base portion embedded in the interlayer insulating film that provides alignment tolerance, and a smaller convex portion protruding from the insulating film surface that serves as the actual bonding contact point. This segmentation allows the large base area to suppress misalignment while the smaller convex portion minimizes dishing occurrence during CMP processing.
Solution Approach 2:
The patent applies local quality by creating a convex portion with different geometric properties than the base Cu electrode. The convex portion has a smaller cross-sectional area and protrudes locally from the bonding surface, concentrating the bonding function in a specific region that is less susceptible to dishing while the larger base area maintains alignment precision.
3Reliability
If dishing occurs on bonding surfaces, then air bubbles are generated at bonding interface, but bond strength is degraded
Solution Approach 1:
The patent implements preliminary action by pre-forming the convex portion that protrudes from the interlayer insulating film before the bonding process. This ensures that during bonding, the convex portions from opposing substrates make contact first, establishing reliable Cu-to-Cu electrical connection before any potential air bubbles can form in dished regions, thereby preventing conduction failures and maintaining bond strength.
Data Source
AI summary
A first semiconductor device includes: a first wiring layer including a first interlayer insulating film, a first electrode pad, and a first dummy electrode, the first electrode pad being embedded in the first interlayer insulating film and having one surface located on same plane as one surface of the first interlayer insulating film, and the first dummy electrode being embedded in the first interlayer insulating film, having one surface located on same plane as the one surface of the first interlayer insulating film, and being disposed around the first electrode pad; and a second wiring layer including a second interlayer insulating film, a second electrode pad, and a second dummy electrode, the second electrode pad being embedded in the second interlayer insulating film, having one surface located on same surface as one surface of the second interlayer insulating film, and being bonded to the first electrode pad, and the second dummy electrode having one surface located on same plane as the surface located closer to the first interlayer insulating film of the second interlayer insulating film, being disposed around the second electrode pad, and being bonded to the first dummy electrode. A second semiconductor device includes: a first semiconductor section including a first electrode, the first electrode being formed on a surface located closer to a bonding interface and extending in a first direction; and a second semiconductor section including a second electrode and disposed to be bonded to the first semiconductor section at the bonding interface, the second electrode being bonded to the first electrode and extending in a second direction that intersects with the first direction.