Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/9434
標題: 銅內連線於熱循環下之應力分析
Analysis of Stress Behavior for Copper Interconnect during Thermal Cyclin
作者: 謝育霖
Hsieh, Yu Lin
關鍵字: copper;銅;interconnect;thermal cycle;stress;內連線;熱循環;應力
出版社: 材料工程學研究所
摘要: 
摘要 在積體電路中,內連線是提供元件與元件間或元件與外在環境的
溝通橋樑,目前最普遍的內連線金屬材料是鋁與鋁合金,但是在ULSI的元
件中,鋁內連線存在電子遷移(electromigration)、電流遲滯(delay)、
應力空孔(voids)與堆積(hillock)等問題。展望未來的製程,找尋新的內
連線材料是迫切的課題。銅有比鋁低的電阻、高電子遷移阻抗、高熱導率
等優點,是最可能的新一代內連線材料。但是銅沒有穩定緻密的表面鈍化
層、銅與介電層附著力差、銅離子與介電層的相互擴散、及銅比鋁高的高
應力等。其中表面鈍化、附著力促進、及擴散阻礙,可由多層結構(
multilayer)來克服。另外銅高應力的問題,對元件可靠度(reliability)
分析是相當重要的部分,是本實驗所要關心的重點。 本實驗將銅內連
線製作成多層結構,於真空中做熱循環與持溫,由於銅膜與基材因熱膨脹
差所造成的試片彎曲,可由雷射曲率量測系統量測曲率,再以stoney方程
式與TEM觀察輔助換算成應力。由應力-溫度曲線圖,來預測銅膜應力的
發展與疏散機制。另外,以持溫的應力-時間曲線圖,經由塑性速率方程
式擬合,確定特定應力溫度範圍銅膜的疏散機制,再由TEM觀察輔助計算
特定疏散機制的活化能,並與形變機制圖(deformation mechanism maps)
做比較。其次,銅膜沈積方位(orientation)對鍍膜表面非常敏感,所以
在多層結構中,不同的鍍銅表面,對銅膜沈積方位的影響也是探討的部份

AbstractInterconnect provide communication between devices and
devices or outside environment in integrated circuit. Aluminum
and aluminum alloy are currently the most commonly used
interconnect materials, However some problems associated with
Al-base material during manufacturing process and service
include electromigration, RC delay, stress voiding and hillocks,
etc. As the size of devices shrink, the search of new
interconnect materials for next generation process is necessary.
Copper is the most prominent candidate for the purpose, Due to
it's low resistance, strong electromigration resistance, high
thermal conductivity, and so on. Before copper can be utilized
as the new interconnect material, several questions which
include surface passivation, poor adhesion, high stress, etc.
One way to solving some of the problems is to use multilayers
which provide passivation function for copper surface and
diffusion barrier function between copper and dielectric film as
well as function as adhesion promoter. Therefore, the analysis
of thermal stress and relaxation mechanism for the multilayer
copper interconnect structure become crucial for the realization
of the copper interconnect.In this experiment, we measured the
curvature changes of the multilayer copper structure during
thermal cycling or isothermal annealing in vacuum by laser
scanning method and converted the curvatures into stress using
stoney formula. Transmission electron microscopy(TEM) was used
to provide extra structure information of the metal film.
Relaxation mechanism of the structure at specific temperature
and stress level was conjectured by fitting the stress-to-time
plot under isothermal annealing with relaxation rate-equation
for differentmechanisms.
URI: http://hdl.handle.net/11455/9434
Appears in Collections:材料科學與工程學系

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