材料分析的程序(Steps of Materials Analysis)-1/2

材料分析實驗的進行的主要步驟有取樣、試片製做、儀器分析、資料解析與歸納、結論等五項。進行分析之前最好先確認材料分析的目的，同時決定所需資料的類別(亦即決定儀器分析方式)，以免浪費時間與金錢。

There are five mains steps in the experiment of materials analysis, they are sampling, sample preparation, instrument analysis, data process and analysis, conclusion. It is better to make clear the objects of the analysis, and decide what kinds of information (i.e. to determine what kinds of analysis to be performed) to avoid wasting time and money.

取樣(Sampling)

正確的取樣是有效率材料分析的第一步驟。所謂「失之毫釐，差之千里」，如果第一個步驟就錯誤，接下來的材料分析，輕者浪費一些人力與物力的資源，重者得到錯誤的結論，而導致後續嚴重的投資損失。

Precise sampling is the first step for efficient materials analysis. It is very important for this step. It will waste time and resource when improper samples are taken. Even more, a big mistake in investment can be made from a conclusion made from this incorrect analysis.

樣品數要足夠，才有足夠可信度的資料；但是又不能太多，否則效率降低，成本增加。以鋁合金時效強化為例，其強度隨者熱處理時間增長，逐漸提升，到達峰值之後，再下降，如圖5所示。要瞭解顯微結構變化與強度變化的關係，最少要取A, B, C三點的樣品做分析，再加取D, E二點的樣品做分析，可更確認顯微結構變化和強度的關係，再多取樣品，則在有限的資源下就會形成浪費。

Confident data come from enough samples in an experiment. However, it will be inefficient if too many samples are included. Considering the example of precipitation hardening (aging strengthening) of Al alloys. After alloying, the alloy is annealed at an adequate temperate. The strength of the Al alloy increases with time, and gradually decreases after reaching its peak value, as shown in Fig.5. It needs at least three samples, A, B, C, to study the relationship between the strength and the microstructure. Two more samples, D&E, will give further results to make things more clear. More samples will result in wasting when resource is limit.

                                                                                  

圖5. 鋁合金時效強化熱處理實驗，樣品強度和熱處理時間關係示意圖。

試片製做

受限於材料分析儀器工作腔體的空間大小和光源與偵測器的特性，樣品必須先經過適當的處理後，變成符合該儀器尺寸和形貌的試片，才能置入材料分析儀器，進行材料分析。

Due to the space limitation and characteristics of instruments, most of samples have to be appropriately processed before being put into the working chamber for analysis.

對掃描式電子顯微鏡(SEM)來說，最基本的試片製做程序是先切割，部份試片包括平面型半導體元件試片，鍍導電金屬後即可進入SEM觀察分析，其餘大部分試片需要進一步鑲埋、研磨、拋光，適當地蝕刻後再鍍導電金屬。一般固態無機穿透式電子顯微鏡(TEM)的試片需雙面研磨拋光減薄至10微米以下，再用渦穴研磨機局部減薄至1微米左右，最後用離子削薄機(ion miller)削薄到100奈米以下的薄區。金屬試片可用雙面電解拋光法，簡單又快速．近代半導體元件試片則多用聚焦離子束(FIB)定點精準切割。要進入歐傑分析儀(AES)或X射線光電子分析儀(XPS/ESCA)的試片必須注意待分析區表面，不要被任何物品(尤其是金屬鑷子)碰觸到，以避免表面汙染。

Traditionally, the basic process for SEM samples is to cutting, mounting, grinding, polishing, etching, and coating, except for a few special types of samples. For almost all solid state inorganic TEM samples, they have to be thinned and polished from both sides to about 10 um thick, and then dimpled to about one micron meter, finially be ion milled down to 100 nm and/or less by Ar ions. Metal samples can be done by twin jet polish, easy and quick. Most of samples of modern semiconductor devices are prepared by focus ion beam (FIB) for the requirement of accurate specified positions. It needs to be very careful to handle samples to be analyzed by Auger or XPS(ESCA), any touch by metal tweezers on the surface will be a serious surface contamination.