半導體晶圓檢測Pt-Cu-Ag探針材料開發

Abstract

探針材料在半導體和綠色能源產業扮演著舉足輕重的角色，在測試環節探針會針對積體電路晶片、印刷電路板、光電封裝品等不同的半導體產品進行測試。在五花八門的金屬合金探針中，Pd-30Ag-30Cu具有高強度、高硬度、良好的導電性等優點。高性能的Pd-30Ag-30Cu 需要通過在真空中熔化並使用連續鑄造法製備成6 mm的合金棒，接著在室溫下進行抽線製程，並在直徑2.83 mm、1.51 mm、0.5 mm 設置檢查點。合金經過800oC固溶熱處理一小時後，硬度從376 Hv下降到252 Hv。金相觀察顯示微觀結構內有等軸的富銀相，其組成為 Ag: Pd: Cu = 52.5: 26.9: 20.6，嵌入在富銅相基體中，組成為 Cu: Pd: Ag = 38.0：32.2：29.8。直徑為 0.5 mm 的細線在 350 °C 下進一步進行時效 1 小時，以達到 425 Hv 的高硬度。同時，近年來隨著Pd價格的飛漲，將合金中的Pd取代成其他元素作為探針的需求也在增長，成為半導體行業的必然趨勢。因此，在本研究中，我們建議 Pt 是替代 Pd 的優選元素，從合金相圖中我們得知 Pt-Cu 與 Pd-Cu 形成相似的顯微結構，Pt 和 Pd 都來自第 8 族，因此它們都擁有相似的化學性質。在整個研究過程中，我們發現組成比為 46.5: 46.5: 7 的 Pt-Cu-Ag 的最高硬度達到了 350 Hv。同時，我們還發現其他成分比可能具有更好的性能，例如 Pt-42.5Cu-15Ag 具有符合需求的 18 μΩcm 電阻率和 272 Hv 鑄態硬度。在本研究中，我們發現當Ag含量超過10%時，合金對抽線過程造成困難，只有進行高溫熱處理後才能繼續抽線過程。由於高溫熱處理導致合金不能發揮其優異的機械性能。同時，高溫熱處理還可以引起合金中的偏析和合金施加塑性變形時的晶粒細化作用。

Probe materials are employed in the semiconductor and sustainable energy industries for the testing of integrated circuit chips, printed circuit boards, and optoelectronic packages. Among the numerous metallic probe alloys, Pd-Ag-Cu has the advantages of high strength, high hardness, and satisfactory electrical conductivity. To produce a high performance Pd-30Ag-30Cu probe, the alloy was vacuum melted and continuously cast into a rod of 6 mm diameter. The as-cast alloy rod was then sequentially cold drawn into coarse wires with diameters of 2.83, 1.51, and 0.5 mm. After solid solution treatment at 800 °C for 1 hr, the hardness decreased from 376 Hv to 252 Hv. Metallographic observations showed a microstructure of equiaxial clusters of Ag-rich phase with a composition of Ag : Pd : Cu = 52.5 : 26.9 : 20.6, embedded in a matrix of Cu-rich phase with a composition of Cu : Pd : Ag = 38.0 : 32.2 : 29.8. The 0.5 mm diameter fine wire was further aged at 350 °C for 1 hr to achieve a high hardness of 425 Hv. Meanwhile, in recent years as the price of Pd ballooned, so the demand of replacing Pd into other element growed as the probe is a must in semiconductor industry. As a result, in this research, we propose Pt is the fine element to replace Pd, from the phase diagram we learn that Pt-Cu form a similar structure with Pd-Cu, Pt and Pd are from group 8 so both of them shows similar chemical properties. Throughout the research, we found that Pt-Cu-Ag with the composition ratio of 46.5:46.5:7 have reached the highest hardness of 350 Hv. At the same time, we also found other composition ratio might have better performance such as Pt-42.5Cu-15Ag have a follow convention resistivity of 18 μΩcm and 272 Hv hardness as-casted. In this research, we found that when the Ag content is over 10%, the alloy cause suffocate to the drawing process, the drawing process can continue only after a high temperature heat treatment is implemented. Due to the high temperature heat treatment cause the alloys do not perform its excellent mechanical properties. At the same time, high temperature heat treatment also can cause phase separation in the alloy and a grain refinement effect when plastic deformation is applied to the alloy.