Development of liquid cooling techniques for flip chip ball grid array packages with High Heat flux dissipations

Abstract

In this paper, development of single-phase liquid cooling techniques for flip chip ball grid array packages (FBGAs) with high flux heat dissipations is reported. Two thermal test chips with different footprints, 12 mm 12 mm and 10 mm 10 mm, respectively, were used for high heat flux characterizations. A liquid-cooled aluminum heat sink with an area of 15 mm (L) 12.2 mm (W) populated by microchannels was designed and fabricated. The microchannel heat sink was assembled onto the chip, using a thermal interface material to reduce the contact thermal resistance at the interface. A variable speed pump was used to provide the pressure head for the liquid cooling loop. The measured thermal resistance results ranged from 0.44 to 0.32 C W for the 12-mm chip case and from 0.59 to 0.44 C W for the 10-mm chip case, both under flowrates ranging from 1.67 10 6 m 3 s to 1.67 10 5 m 3 s. An analytical model of the flow and heat transfer in microchannel heat sinks is also presented. Computational predictions agree with the measurements for pressure drop within 15% and thermal resistances within 6%. The analytical results indicate that thermal interface resistance becomes a key limitation to maximizing heat removal rate from electronic packages.

Power delivery, signaling and cooling for 2D and 3D integrated systems

“…Once assembled, an encapsulant is applied between the die and substrate to seal the interface between the fluidic I/Os and the vias in the substrate (Figure 2.18). This approach is radically different from previously reported research [35,36] in the area of fluidic interconnects for ICs. In order to characterize the fluidic interconnects and the microchannel heat sink and perform temperature measurements, thin-film Pt heaters/thermometers were fabricated on the silicon die.…”

Numerical study of the inlet/outlet arrangement effect on microchannel heat sink performance

“…Since then, microchannel heat sink performance using different substrate materials and channel dimensions have been studied extensively in the past two decades. These studies can be categorized into theoretical [3][4][5][6], numerical [7][8][9][10][11], and experimental approaches [12][13][14][15][16]. In the theoretical approach, the main objective is to develop design schemes that can be used to optimize microchannel heat sink performance.…”

Heterogeneous 2.5D integration on through silicon interposer

“…Without compromising processing speed, the integration of multi-chips in one interposer on the package tends to generate higher heat density, which needs to be addressed in the 2.5D or 3D package design. [102][103][104][105][106][107][108][109][110][111][112][113][114][115] A schematic of the cooling concepts is illustrated in Figure 50.…”