應用非接觸量測方式探討動態負載對覆晶球柵陣列 構裝元件變形與壽命之影響

Using Non-contact Measurement Technique in Investigating the Deformation and Life of Flip Chip Ball Grid Array Components

陳文政(Wun-Jheng Chen)

指導教授 ： 陳永樹

元智大學/工程學院/機械工程學系/碩士(2013年)

https://doi.org/10.6838/YZU.2013.00342

摘要

電子元件在運送或動態使用環境下，往往會受到振動所產生之變形與應力。本研究針對典型之隨機振動環境下，覆晶球柵陣列構裝(FCBGA)之電子元件的錫球，所受到之實際振動變形應力加以探究。並從電路板受到振動之模態形變著手，研究此變形曲率與裝置於其上之FCBGA元件受力之關聯性。
實驗首先利用掃描式雷射都卜勒測振儀(Scanning Laser Doppler Vibrometer - SLDV)，來量測電路板在隨機振動中之自然頻率與變形量，擷取IC元件下之錫球位移量，再將位移量根據理論公式求出錫球之應力與應變值。
實驗中發現，當激振頻率達第一自然頻率時，電路板因而產生共振，對IC元件形變量有顯著之影響。在探討電路板形變曲線與錫球應力變化的關聯性時，發現當系統處於第一模態，電路板之上、下振動變形，在位移最低點時，其曲率半徑較之在位移最高位置時之值為小，此時產生之形變也較大，故此時錫球受到最大之應力。而以前三個模態比較，以第一模態所產生之變形對元件造成之應力為最大。
關鍵字：形變曲線，覆晶球柵陣列構裝，隨機振動，掃描式雷射都卜勒測振儀

關鍵字

形變曲線 ； 覆晶球柵陣列構裝 ； 隨機振動 ； 掃描式雷射都卜勒測振儀

並列摘要

The electronic components always subjected to vibration induced deformations and stressed either during transportation or when using in dynamic environments. This study took a test specimen of flip chip ball grid array (FCBGA) component which was mounted on a printed circuit board (PCB) for investigating the vibration mode shapes and the induced stresses on the solder balls of component. Relationship on the radius of curvature of the deformation and the stresses on the components are calculated.
In the experiment excited with random vibration, the natural frequencies and mode shapes of the PCB assembly were measured with a Scanning Laser Doppler Vibrometer (SLDV) firstly. A series of the dynamic deformation under the FCBGA package were measured with the SLDV. This deformation was then fitted into the theoretical equation for calculating the displacement and strain of the solder balls.
It was found in the experiment that under resonance at the first natural frequency, the PCB deforms most comparing with those at the second and third natural frequencies. When focusing on the first mode shape, it can be found that the curvature of the deformed PCB has the lowest value at the lowest position comparing with that at the highest position during the up and down vibration motions. Thus, this deformation induced stress is larger when the PCB is at the lowest position. Among the deformations of all the first three mode shapes, the first mode causes much severe damage to the solder balls of components.
Key words: Deformation Curve, FCBGA, Random vibration, SLDV

並列關鍵字

Deformation Curve ； FCBGA ； Random vibration ； SLDV

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