EN 62047-13-2012 pdf download.Semiconductor devices -Micro-electromechanical devices -Part 13: Bend- and shear- type test methods of measuring adhesive strength for MEMS structures.
4.1 General
This standard specifies the adhesive testing methods between a columnar test piece (see Figure 1) and substrate. Displacement or force is applied to a columnar test piece at a constant speed and the force at delamination is measured to analyze the adhesive strength between the columnar test piece and substrate. A knife edge shape with tapered tip is utilized as the loading tool to apply the force to a columnar test piece. The angle of the knife edge is changed by loading types of measuring adhesive strength as follows.
In case of measuring adhesive bend strength by applying bending force at the end of a columnar test piece (bend type test), the knife edge of loading tool is used by slanting its apex in the upper direction against the test piece as shown in Figure 2 a). In such a case, it is easier to align the loading tool and a test piece since point load is applied at the end of the columnar test piece. Attention should be drawn to the fact that the bend type test is not pure bending. which includes compression component to the columnar root. The compression component increases by increasing the contact angle of the knife edge. In order to minimize the effect of compression component. the contact angle of the knife edge (0b) should be within a range of from 10 to 20.
In case of measuring adhesive shear strength by applying shear force on the lateral face of a columnar test piece (shear type test), line load Is applied to the test piece using a loading tool which Is parallel to the lateral face of the cylinder as shown in Figure 2 b). In such a case, the test apparatus should have a precise alignment system, which can align the knife edge parallel to the lateral face of the cylinder. Or alternatively, the knife edge of loading tool is used by slanting its apex in lower direction against the test piece as shown in Figure 2 b) to minimize the effects of bend stress (see Clause A2).The angle error (°) should be within a range of from 0 to 15D. It should be noted that the test results from the bend type test are affected by the aspect ratio (!c/D), when the aspect ratio is less than 1.2. See Clause A.2. In addition, the columnar test piece with the aspect ratio of less than 0,5 should not be applied in the bend type test; because the effects of the aspect ratio on the shear and the compression stress on the adhesive Joint area significantly increase when the aspect ratio decreases. See Clause A.2 and Clause A.3.
The test piece should satisfy the following two items:
a) It Is recommended that the dimensions of a test piece, such as the columnar diameter and length., are in the same order as the size of parts of a device to be evaluated:
b) Every gap between the test pieces (S) should provide more than twice compared with both the diameter of columnar test piece (D) and the length of test piece (‘a) to prevent each piece from having an influence on the test of adjacent test piece (see Figure 1). In addition, the gap (S) should be sufficiently larger than the width of the knife edge tip of the loading tool (Ik) to avoid loading two columnar test pieces at the same time. See Figures 1 and 3.
6.2 Preparation of test pieces
A number of columnar test pieces with the same manufacturing process and conditions are obtained, since a plurality of columnar test pieces are prepared on the same substrate.
The test pieces should satisfy the following two items:
a) Test pieces should be prepared on a substrate through an almost identical manufacturing process and under the same manufacturing conditions as those applied when fabricating the thin film of the device to be evaluated;
b) More than ten columnar test pieces should be prepared on the same substrate at the same time. Then, adhesive testing should be performed using more than ten columnar test pieces under the same testing conditions (see Clause Al).
7 Test conditions
7.1 Method for gripping
Substrate of test pieces shall be fixed according to the following two items:
a) Substrate of test pieces shall be fixed at test device ensuring not to move during adhesive strength test. Clauses A.2 and A.3 of IEC 62047-2:2006 shall apply;
b) Substrate of test pieces shall be fixed such as the loading direction of the test device Is parallel with the substrate surface. See 7.3.
7.2 Speed of testing
Displacement speed or loading speed should be constant. As the speed of testing will depend upon the testing environment, the type of testing machine employed and the stiffness of the test piece, the speed shall be the one which is more suitable for the particular combination of environment, material, test piece, and testing machine. Generally, the speed of testing should be chosen properly depending on the application of the materials.EN 62047-13-2012 pdf download.

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