The current state of quantum device maturity proposes the use of removable, reusable interconnection means between such device and their classical microelectronic measurement system. One such means is a land grid array (LGA) socket, used pervasively in microelectronics but relatively untested at cryogenic temperatures necessary for most quantum technologies. This article investigates two distinct commercially available LGA socket technologies with respect to contact resistance performance under cryogenic temperature measurement conditions. Test methodologies were successfully developed for both sockets, demonstrating predictable and repeatable contact resistance values during multiple excursions down to 1.5 K and a single excursion to 10 mK. The experimental data show that contact resistance of individual interconnection sites decreased from 30 to 40 mΩ at room temperature to 14-17 mΩ at 1.5 K and to 6-8 mΩ at 10 mK, thus supporting their reliable use in cryogenic measurement applications. Theoretical calculations based on the construction of the microspring socket validated that measured values behaved in a manner that was consistent with temperature-dependent changes in resistivity of the metals comprising the socket interconnection. Spring deflection allowances compensated for any temperature-driven movement of components within the assembly, thus enabling predictable resistance behavior. Regarding the elastomer socket, the high coefficient of thermal expansion (CTE) of the elastomer bulk material induced large variations in socket compression across the temperature range investigated. Sufficient compression to provide consistent contact resistance values at cryogenic temperatures imposed the need for very high compression at room temperature, which may place into question the longer term integrity of this solution. Nevertheless, a preliminary investigation (five cryogenic cycles and subsequent construction analysis) did not reveal any degradation in either socket type.

中文翻译：

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量子测量所需低温下平面栅格阵列插座的接触电阻行为


量子器件成熟度的当前状态建议在此类器件与其经典微电子测量系统之间使用可拆卸、可重复使用的互连装置。其中一种方法是平面网格阵列 (LGA) 插座，广泛用于微电子领域，但在大多数量子技术所需的低温下相对未经测试。本文研究了两种不同的商用 LGA 插座技术在低温测量条件下的接触电阻性能。两种插座的测试方法均已成功开发，展示了在低至 1.5 K 的多次偏移和低至 10 mK 的单次偏移期间可预测和可重复的接触电阻值。实验数据表明，各个互连点的接触电阻从室温下的 30 至 40 mΩ 降至 1.5 K 时的 14-17 mΩ 和 10 mK 时的 6-8 mΩ，从而支持其在低温测量应用中的可靠使用。基于微弹簧插座结构的理论计算验证了测量值的表现方式与构成插座互连的金属电阻率随温度变化的变化一致。弹簧挠度余量可补偿组件内任何由温度驱动的部件移动，从而实现可预测的阻力行为。对于弹性体承窝，弹性体散装材料的高热膨胀系数 (CTE) 导致在研究的温度范围内承窝压缩发生较大变化。 要在低温下提供足够的压缩以提供一致的接触电阻值，就需要在室温下进行非常高的压缩，这可能会对该解决方案的长期完整性产生疑问。然而，初步调查（五次低温循环和随后的结构分析）并未显示任何一种插座类型有任何退化。