Semiconductor Fuse Element Laser Cutting Corrosion Protection
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Solution Overview
Problem
Existing semiconductor device manufacturing processes face challenges in achieving stable laser cutting of fuse elements while maintaining corrosion resistance, as the removal of protective films exposes the fuse elements to moisture, leading to corrosion and cracking, which compromises the integrity of the insulating film and allows moisture ingress.
Innovation Solution
A semiconductor device design where a uniform silicon nitride film covers the front surface, and a porous insulating film is formed underneath, allowing laser cutting from the rear surface without exposing the fuse element, thus preventing corrosion by maintaining a protective layer post-cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silicon nitride film is formed on the fuse element to improve corrosion resistance, then the fuse element is protected from moisture, but the laser cutting stability deteriorates because the film absorbs laser radiation
Solution Approach 1:
The patent changes the spatial dimension of the protective film by forming it on the side surfaces and lower portion of the fuse element while deliberately leaving the upper portion exposed. This dimensional differentiation allows the protective film to prevent moisture ingress from lateral directions without interfering with laser cutting from the upper direction, thereby resolving the contradiction between corrosion resistance and laser cutting stability
Solution Approach 2:
The patent applies local quality by creating a non-uniform protective film configuration where the side surfaces and lower portion have protective coverage while the upper portion remains exposed. This localized protection strategy targets the specific areas most susceptible to moisture ingress (side surfaces and bottom) while avoiding laser interference zones, thus achieving both corrosion resistance and cutting stability
2Manufacturing precision
If the protective film is removed to enable stable laser cutting, then the laser cutting stability improves, but the corrosion resistance deteriorates because the fuse element is exposed to moisture
Solution Approach 1:
The patent applies preliminary action by pre-forming the protective film on the side surfaces and lower portion of the fuse element before the laser cutting process. This advance preparation ensures that when the fuse element is later cut by laser, the protective film is already in place to prevent moisture ingress into the exposed cut surfaces, thereby maintaining corrosion resistance while enabling stable laser cutting
Solution Approach 2:
The patent implements preliminary anti-action by pre-establishing the protective film barrier on the side surfaces and lower portion to counteract the potential harm of moisture ingress that would occur after laser cutting. This preventive measure is put in place before the cutting operation, anticipating and preventing the corrosion problem that would otherwise result from exposing the fuse element to moisture
3Reliability
If a thick silicon nitride film is formed to enhance corrosion protection, then the corrosion resistance improves, but the laser cutting becomes unstable due to increased laser beam absorption
Solution Approach 1:
The patent applies local quality by forming the protective film with varying thickness and coverage: the side surfaces and lower portion have the protective film (providing corrosion resistance) while the upper portion is intentionally left without film (enabling stable laser cutting). This localized differentiation resolves the contradiction by providing protection only where most needed while avoiding laser interference zones
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively inhibits corrosion at the cut portion of the fuse element and prevents moisture ingress, ensuring the semiconductor device's reliability and longevity by maintaining a protective barrier around the cut surface.
Implementation Method 1
a front surface of a semiconductor device is covered with a silicon nitride film having a uniform thickness
Implementation Method 2
laser light can be radiated from a rear surface of a semiconductor substrate forming the semiconductor device and the laser light can be collected at the fuse element formed on an oxide film formed on a front surface of the semiconductor substrate, thereby cutting the fuse element
Implementation Method 3
a porous insulating film is formed under the silicon nitride film
Data Source
AI summary
A corrosion-resistant semiconductor device includes fuse elements that can be cut by laser light. An upper portion of the fuse elements is covered with a porous insulating film so that, when laser light irradiated from a rear surface of a semiconductor substrate is collected at selected fuse elements, the fuse elements generate heat, expand, and rupture. An array of intersecting metal lines forming windows is disposed over the fuse elements to permit rapid expansion of the fuse elements when irradiated with the laser light. A silicon nitride film having a uniform thickness is formed on a front surface of the semiconductor device to prevent entry of moisture.