金屬微成形技術是一項正在發展中的精密工業技術，其具有許多較MEMS技術佳的優點，例如生產效率高、成本低和產品可具複雜之幾何外形等。不過，當尺寸縮小至微米等級時，則其材料之機械性質會有明顯的變化，而這種與巨觀性質有所差異的現象我們稱之為尺寸效應（size effect）。
有關尺寸效應的影響於近十年來開始，有越來越多的學者投入相關研究當中，但至今尚無法定義出明確的機械性質與其實驗之方法。因此本研究藉由實驗來了解尺寸效應的影響。並依據實驗結果和相關參數的比較，可獲得銅材料在微觀尺寸的特性。
本研究之研究重點在於討論specimen size effect和grain size effect對於銅金屬材料微成形的機械性質之影響。首先，選取五種不同厚度之銅金屬平板作為實驗用之材料。由於ASTM規範中的標準尺寸（E8-M standard specimens）對於微觀拉伸試驗而言似乎太大，故本研究之實驗以將ASTM之最小拉伸試片（E8-M subsize specimens）的外形，以及等比例縮小最小拉伸試片外形成1/2來製作實驗用之試片，探討外形縮小1/2後材料塑流應力曲線之變化，以求得尺寸縮小過程中影響塑流應力曲線變化之重要因素，並且在實驗過程中利用熱處理方法改變試片內部之晶粒大小進行實驗，以求得內部晶粒尺寸的改變對於材料之塑流應力曲線的影響，以作為日後在微觀機械性質測試的參考。

Metal micro-forming process is a developing technology in precision manufacturing. This technology has many advantages over conventional MEMS technology, such as high producing efficiency, low cost, and the ability to produce products with complicated geometrical shape, etc. But when the dimensions reduce to the micro scale, the material properties change dramatically due to the reduction of dimensions. This is called the “size effect”. This effect causes a lot of problems with further research.
The research on metal micro-forming has been developed more and more since ten years. However, neither a correct methodology nor a clear micro mechanical property has been well determined. Hence, in this research several experiments are carried out to point out the influence of “size effect”. According to comparisons between the experiment data and relevant parameters, the material characteristics in micro scale can be found.
In order to find the mechanical properties in micro scale, this study shows the effect of specimen size and grain size on the micro tensile test of copper material. Firstly, five copper micro-sheets with different thicknesses have been chosen for the experiment materials. Because the minimum standard test piece formulated in ASTM is still too big for this micro tensile test, this study decide to shrink the sample size of specimen shape to 1/2 . This way is able to get the important factor which influence the flow stress on the micro tensile test. Secondly, these samples of different grain size are made by heat treatment. Then these samples of different grain size are used to conduct the experiment in the process. According to the experiment result, the change of flow stress which is influenced by the various grain size can be found. Finally, the change of the mechanical behavior between specimen size and grain size is obtained.

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