# Reproduction Assumptions For arXiv:2510.11461

Source: [arXiv:2510.11461](https://arxiv.org/abs/2510.11461), submitted 2025-10-13.

## Paper-Specified Targets

- Physics: 3D steady heat conduction with internal heat generation, plus transient heating curves for TDP comparison.
- GPU heat flux / power density: the model description reports `100 W/cm^2`; later sweeps compare `100 W`, `200 W`, and `300 W` TDP cases.
- Cooling: top forced convection coefficient range `150-350 W/(m^2*K)`; bottom natural convection coefficient `10 W/(m^2*K)`.
- Interposer comparison: silicon versus h-BN.
- h-BN thermal conductivity: in-plane `751 W/(m*K)`, through-plane range `2-20 W/(m*K)`.
- Silicon thermal conductivity: `130-150 W/(m*K)`.
- Reported qualitative checks: h-BN lowers GPU hotspot temperature versus Si, HBM spreading lowers hotspot temperature, and h-BN thickness benefits level off around `300 um`.
- Reported numeric anchors: approximately `20 degC` hotspot reduction for h-BN versus Si under high heat flux; approximately `315 degC` hotspot for the `20 HBM/layer x 1 layer` case.

## Missing Details

The paper does not publish a COMSOL `.mph`, mesh, exact package dimensions, layer thicknesses for every chip/package component, material properties for all non-interposer layers, TSV dimensions/count, exact HBM footprint/placement, heat sink geometry, solver settings, or raw numerical tables.

## Working Assumptions

This reproduction therefore builds a representative, parameterized COMSOL model and checks trends rather than claiming one-to-one numerical identity.

- Stack footprint: representative square package-scale model.
- Layer order: substrate, TSV/interconnect representation, HBM stack layer(s), interposer, GPU, and heat sink/spreader.
- Heat source: applied in GPU domain as volumetric heat generation corresponding to TDP or heat flux assumptions.
- h-BN material: anisotropic conductivity, with high in-plane conductivity and configurable through-plane conductivity.
- Baseline silicon: isotropic conductivity.
- HBM distribution sweep: represented by the number of HBM vertical layers and per-layer lateral spread, matching the paper's `20x1`, `10x2`, `5x4`, `4x5`, `2x10`, and `1x20` cases.
- Acceptance: numeric probes for finite `Tmax`, lower `Tmax` for h-BN than Si, improved `Tmax` with HBM spreading, and diminishing returns near `300 um` h-BN thickness.