Research On Packaging Technology Of High Performance Thermoelectric Cooler

Thermoelectric cooler(TEC),is a solid-state refrigeration device widely used in spot cooling,having advantages such as no refrigerant,no moving parts and convenient refrigeration/ heating switching.It can achieve serial connection of TE legs by metal layers on the substrate and active cooling of hot spots based on Peltier effect.At present,the performance of ceramic substrates using in TEC packaging is insufficient,which affects performance and application of TEC products,for example: 1)their pattern accuracies are low,which means that the power density of TECs are very poor,and these TECs are difficult to miniaturize;2)at present,when used for preparing a multi-stage TEC,additional metal lines on substrates are needed to achieve the interconnection of stages,which will not only result in poor integration,but also reduce the reliability of the module.Direct Plated Copper(DPC)ceramic substrate,a new type of ceramic substrate prepared by semiconductor micromachining technology,having following advantages: the pattern has a high precision(30-50 μm),the vertical interconnection of the upper and lower surfaces of the ceramic substrate and so on,are considered to solve the problem of poor performance of ceramic substrate using in TEC package.In this study,single-stage,multi-stage and mini TECs are prepared one after another,and the properties of the prepared TEC samples were tested.The main research contents and innovations are as follows:1)TECS were packaged using three different types of ceramic substrates(Direct Plated Copper DPC,Direct Bonded Copper and Thick Printing Ceramic TFC),and the influence of preparation process of ceramic substrates on TEC performance was analyzed.The results showed that the single-stage TECs using DPC substrate had the best performance.2)Based on vertical interconnection characteristics of DPC ceramic substrates,a new type of multi-stage TEC was developed using DPC substrate.The performances and reliability of these multi-stage TECs were tested.The results showed that the prepared multi-stage TEC had high reliability.3)Based on the characteristics of high graphic precision of DPC ceramic substrate metal layers,mini TECs were developed and their performances were tested.The results showed that the prepared mini TEC met the application requirements.