BS EN 62047-14:2012 pdf download
BS EN 62047-14:2012 pdf download.Semiconductor devices ——Micro-electro mechanical devices Part 14: Forming limit measuring method of metallic film materials.
Grids shall be marited to the surface of the testing sample to measure the localized and overall deformation of the film material. The grid consists of a pattern of small circles or rectangles It is recommended to arrange the grid patterns with an interval range from 50 pm to 200 pm and that the thickness of the grid is less than 10 % of the specimen thickness.
NOTE See Figure A.3 for detaded grd pattern.
5 Test procedure and analysis
5.1 Test procedure
In a FLD test, the following items from a) to e) are steps to obtain a localized fracture of a specimen which is firstly observed. Then the values of a major strain and a minor strain which are used to quantify the deformation of the specimen will be measured.
a) Preparation of the specimen
Specimens with different aspect ratios are prepared to conduct the test.
NOTE I Both the positive and negative legion of the FLD curve can be obtained by varying the aspect ratio of tile specimen and th, lubricant
b) Grid marking on the specimen
Appropriate marling conditions which have a lesser effect on the microstructure and the properties of materials should be applied in the grid marking since the thickness of the film is relatively smaller,
NOTE 2 See Annex B for detail expression of several grid marking methods.
C) Gripping the specimen
In order to measure the strain only in the testing region, it is important that the sample should be clamped without any sliding. Also. pre-fracture should not occur when it is being clamped.
NOTE 3 See Annex C for several recommended gripping methods.
d) Moving the punch until the specimen fails
The hemispherical punch moves by controlling the constant crosshead speed of equipment until the localized fracture of the specimen Is first observed.
e) Measuring the major and minor strains of deformed specimen
Major and minor strains of the deformed specimen are measured representatively using the digital camera module with a high magnifying power lens. The recommended magnification factor of the camera lens Is less than 5 pmlpizel in order to measure the strain precisely.
NOTE 4 See Annex D for strain measuring method.
f) Construct the FLO by plotting the measured maor and minor strains (refer to Figure 4),
c.2Bonding method
As shown in Figure C.2, a gripping method using adhesive bonding can be adopted in the test.Either upper or lower adhesive can be used if they satisfy the no slip condition. At this point, itshould be ensured that the adhesive does not inivade the round part of the upper die edge.Additionally, it is recommended that the upper and lower thicknesses of the adhesive layerrespectively should not exceed 10 % of the specimen thickness.
Major and minor strains of the deformed specimen can be measured representatively using the digital camera module with a high magnifying power lens. As shown in Figure Dl, the digital camera module shall be located so that the line of sight is perpendicular to the surface of the deformed specimen. Alternatively, the digital camera is fixed and the deformed specimen can be moved. The image captured from the digital camera shall be converted to real scale data by the pixel calculating algorithm described in Figure D.2. Manual calculation of the strains can be adopted, but using a software which can calculate the strains would be convenient The detailed step-by-step procedure for the strain measurement is as lollows.
Step 1 Install the high magnified digital camera over the deformed specimen so that the screen displayed from the camera including the grid pattern of the specimen can be observed cleady
Step 2. Manipulate the software so that one o more grid patterns on the region of interest of the deformed specimen appear(s) on the monitor.
Step 3. Concerning the corresponding ellipse, calculate the major and minor deformations by counting the pixels.
