SemiSimTech

Project

Edge Reliability Simulator (Moisture Ingress)

A visual reliability demo that explains why edge regions often experience elevated exposure earlier than interior regions. This interactive version uses a simplified diffusion-inspired model so you can change key assumptions and immediately see how probe curves and a near-edge risk index respond.

Simulation Physics • Diffusion Reliability Intuition

Distance to edge

Near-edge regions usually respond earlier because the exposure source enters from the boundary and propagates inward over time.

Barriers

Sealing or passivation-like regions slow penetration and delay how quickly deeper areas see elevated exposure.

Fast paths

Interfaces, gaps, or weakly protected regions can accelerate transport relative to the surrounding bulk.

Figure 1. Cross-section intuition

static explainer
Edge ambient source Barrier seal / passivation Package / material interior Near-edge ROI earlier response higher early risk Interior probe delayed rise slower exposure Transport moves from the exposed edge toward deeper regions

This figure establishes the basic geometry. Moisture ingress begins at the exposed boundary, then competes with barrier protection and transport distance before it reaches the regions we care about.

Figure 2. Time progression

static explainer
Early Middle Late edge region becomes wet first front advances inward deep interior eventually responds

The simulator curves are just another way to read this story. Earlier times mainly reflect edge behavior; later times reveal whether the front has propagated far enough to influence deeper regions.

Figure 3. Strong barrier vs weak barrier

tradeoff view
Strong barrier Weak barrier smaller transmitted flux larger transmitted flux

Increasing barrier strength in the model is a compact way to represent better sealing, slower permeation, or a more protective path from the edge to the active region.

Figure 4. Bulk path vs fast path

failure acceleration view
Mostly bulk path Fast path / interface slower, distributed transport preferred route accelerates ingress

The fast-path factor does not mean all material suddenly diffuses faster. It means some route, interface, crack, seam, or under-protected region becomes disproportionately important.

Probe curves

The near-edge probe should generally rise earlier than the interior probe. The spacing between them is a compact measure of edge dominance.

Risk index

The risk index summarizes exposure in a near-edge region-of-interest. It moves earlier when fast paths dominate and later when barriers are strong.

How the simulator works

The model computes simplified normalized exposure curves C(t) using a diffusion-inspired delay term. It is not a full PDE solver, but it preserves the main physical ideas:

  • Open boundary behaves like a persistent source at the edge
  • Distance delays the response deeper into the structure
  • Barrier strength slows effective transport
  • Fast paths increase effective transport and accelerate exposure

Figure 5. From environment to failure risk

concept chain
Environment humidity, soak, bias, heat Ingress path edge, seam, interface Local exposure concentration increases Material change corrosion, delamination, drift Reliability risk performance loss / failure

The current lab only models the left half of this chain: exposure formation and edge-weighted risk. That is enough for intuition-building, even before adding chemistry-specific degradation kinetics.

Figure 6. Parameter-to-meaning map

reading guide
Control Main meaning Typical visual effect
distanceNear how close the ROI is to the exposed edge smaller value shifts near-edge response earlier
distanceFar how far the interior probe sits from the edge larger value delays the interior curve
diffusionRate overall transport speed higher value moves both curves leftward in time
barrierStrength protective slowing effect higher value delays response and softens early rise
fastPathFactor dominance of preferred ingress routes higher value sharpens and advances edge-sensitive behavior
roiWeight how strongly the risk metric emphasizes near-edge behavior higher value makes the risk index more edge dominated
timeMax visible observation window changes how much of the story is shown on screen

Assumptions and scope

important note

This lab deliberately compresses several physical effects into a few intuitive knobs. That makes it useful for teaching and for early framing discussions.

  • normalized exposure rather than absolute moisture concentration
  • effective barrier behavior instead of a multilayer calibrated stack
  • effective fast-path behavior instead of explicit crack/interface geometry
  • risk index as an intuition metric, not a qualified lifetime model

How to read the two plots together

The probe curves answer: when do different physical locations begin to feel the ingress? The risk index answers: how serious is the edge-focused exposure for the chosen region-of-interest? When both shift earlier, the system is becoming more vulnerable. When the near-edge curve moves much earlier than the interior curve, the device is becoming more edge-dominated.

Real-world interpretations

Depending on the application, this same intuition can be reused for package-edge moisture ingress, sidewall exposure, passivation weakness, adhesive seam leakage, or other edge-initiated reliability problems. The specific chemistry may change, but the geometric story often stays similar.