| 摘要: | 晶圓測試(wafer test)在測試機與IC 焊墊間需要有微探針模組做為接觸媒介，陶瓷製的絕緣probe head 是個關鍵性的零件，數以千計的微細探針分佈在20×20 mm2 的面積上，使探針在測試過程中能準確的定位與導引。高密度微孔陣列為probe head 的重要特徵，陶瓷板上微孔陣列的製造精密度與準確度會影響到探針卡測試的正確性；因此，除了微孔的尺寸公差要求外，微孔與微孔間的位置度誤差更需要嚴密的控制。圖三為一具有3358 個111μm微孔的陶瓷probe head。陶瓷板材的微孔製作，因材料的脆性特徵，需要以啄鑽工法(peck drilling)以高精度的CNC 機具製作。根據前期計畫(NSC 97-2221-E-034-007)的分析結果：鑽削循環中，鑽針的退刀距離約為進刀距離的兩倍，才能有足夠的散熱空間，保持刀具的鋒利性；陶瓷板材的百微米微孔加工在8000rpm、進給率5mm/min 的加工條件下，在64.2mm 的切削行程內，刀具仍處於堪用狀態。本計畫擬發展電腦視覺系統，透過數位影像處理、特徵辨識與量測等程序，進行微孔陣列的位置度偏差檢測；並規畫刀具磨耗實驗觀察不同階段鑽針切刃邊與刀唇的磨耗狀態。本研究提出兩年期的研究計畫，第一年計畫：建立微孔陣列電腦視覺系統，以光學顯微鏡取像，針對探針卡元件probe head 的高密度微孔陣列進行影像量測與特徵辨識，並提出微孔陣列位置度誤差分析方法，以評估探針卡針測點的整體性位置度偏差；第二年計畫：建立微鑽針影像量測模組，設計製作具角度調整功能的測試平台，進行鑽針頂面的影像量測與刀具磨耗分析，探討陶瓷微鑽切削行程與切削速度對刀具壽命的影響，決定分析案例的最適換刀時機，使微型鑽針能發揮最大的經濟效用，並得到高品質的微孔特性。本計畫的完成，將可提供以微鑽針製程製作陶瓷微孔陣列之製造與評估方案。
In wafer probing, a micro-probe module is serviced as a contact interface between wafer tester and IC welding pads. Probe head made by insulating ceramic is a critical component for probe card. Thousands of micro-drill are distributed over a 20×20 mm2 square area to ensure the probes can be guided and positioned exactly. High density micro-holes array is an important feature, and its precision and accuracy in fabrication will affect the probing correctness of the probe card. Therefore, in addition to meet the request on dimensional tolerance, the positional error among micro-holes must be controlled strictly. Figure 3 shows a ceramic probe head having 3358 micro-holes with diameter of 111 . In micro-holes fabrication, because of the brittle property of ceramic material, the peck drilling method is taken and implements by a high precision CNC machine. According to the results of the earlier project (NSC 97-2221-E-034-007), the return distance in peck drilling cycle must be two times of the machining distance, in order to spread out the heat generating in cutting and to keep the sharpness on tool tip. Under the conditions that with a spindle speed of 8000 rpm and a feed rate of 5mm/min, after a drilling stroke of 62.4 mm, the drill is still in use. This project will develop a computer vision system by methods of digital image treatment, feature recognition and measurement, to examine the positional error of the micro-holes array and observe the wear on the chisel edge and the lip of the micro-drill in various drilling stages. This study proposes a two-year project. In the first year scheme, to establish a computer vision system for micro-hole array measurement; in the system, an optical microscope is used to catch the image of the micro-holes array on the probe head, and digital image treatments are implemented feature recognition. In addition, this study proposes a positional error analysis method for micro-hole array to evaluate the possible probing correctness of the whole probe card. In the second year scheme, to establish an image measuring module for the micro-drill; a measuring platform with angular adjustment function is designed and fabricated to catch the image of the top surface of micro-drill. A series of tool wear experiments will be conducted to explore the influences of machining stroke and cutting speed on tool life, and to decide the optimal time for tool replacement. Therefore, the micro-drill would have a maximum economical utility and obtain a high quality micro-hole. The finish of this project could provide useful references for micro-holes array fabrication and evaluation by using the micro-drilling process. |
