Effect of Fabrication on High Cycle Fatigue Properties of Copper Thin Films

Park, Jun Hyub; An, Joong Hyok; Kim, Yun Jae; Choi, Hee Cheul

doi:10.1007/s10338-008-0837-y

Cited by 7 publications

(5 citation statements)

References 22 publications

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“…The micro-tensile tester was constructed according to a new design specially made for the closed-loop testing of thin films [7,9]. It uses the voice coil of a speaker as the actuator.…”

Section: Specimen and Test Machinementioning

confidence: 99%

“…The range and nominal scale factor of the capacitance sensor were 1250 μm and 125 μm V −1 , respectively. An image-based displacement measurement system using the CCD camera was also used to measure the extension of the gauge length between two marks on the specimen [9]. The CCD camera had an image size of 1296 × 964 pixels.…”

Section: Specimen and Test Machinementioning

confidence: 99%

“…In this study, tensile tests were performed on the beryllium-copper (BeCu) alloy which furnishes the best combination of electrical conductivity, corrosion resistance and mechanical strength necessary for numerous electronic and electro-mechanical devices. The test system used in this study was developed by the authors [6][7][8][9] and was comprised of two noncontact displacement measuring systems. One system is based on the principle of capacitance micrometry with a resolution of 10 nm and measures the displacement between grips.…”

Section: Introductionmentioning

confidence: 99%

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Reliability design and assessment of a micro-probe using the results of a tensile test of a beryllium–copper alloy thin film

Park

Shin

2011

J. Micromech. Microeng.

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This paper describes the results of tensile tests for a beryllium–copper (BeCu) alloy thin film and the application of the results to the design of a probe. The copper alloy films were fabricated by electroplating. To obtain the tensile characteristics of the film, the dog-bone type specimen was fabricated by the etching method. The tensile tests were performed with the specimen using a test machine developed by the authors. The BeCu alloy has an elastic modulus of 119 GPa and the 0.2% offset yield and ultimate tensile strengths of 1078 MPa and 1108 MPa, respectively. The design and manufacture of a smaller probe require higher pad density and smaller pad-pitch chips. It should be effective in high-frequency testing. For the design of a new micro-probe, we investigated several design parameters that may cause problems, such as the contact force and life, using the tensile properties and the design of experiment method in conjunction with finite element analysis. The optimal dimensions of the probe were found using the response surface method. The probe with optimal dimensions was manufactured by a precision press process. It was verified that the manufactured probe satisfied the life, the contact force and the over drive through the compression tests and the life tests of the probes.

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“…The micro-tensile tester was constructed according to a new design specially made for the closed-loop testing of thin films [7,9]. It uses the voice coil of a speaker as the actuator.…”

Section: Specimen and Test Machinementioning

confidence: 99%

Section: Specimen and Test Machinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reliability design and assessment of a micro-probe using the results of a tensile test of a beryllium–copper alloy thin film

Park

Shin

2011

J. Micromech. Microeng.

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“…The micro-tensile tester used in these tests was constructed according to the new design especially for closed-loop testing of thin films by the authors [28,29]. It uses a voice coil of a speaker as an actuator.…”

Section: Specimen and Test Setupmentioning

confidence: 99%

Specimen alignment in an axial tensile test of thin films using direct imaging and its influence on the mechanical properties of BeCu

Kang¹,

Park²,

Shin³

et al. 2010

J. Micromech. Microeng.

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This paper proposes a new system for verification of the alignment of loading fixtures and test specimens during tensile testing of thin film with a micrometer size through direct imaging. The novel and reliable image recognition system to evaluate the misalignment between the load train and the specimen axes during tensile test of thin film was developed using digital image processing technology with CCD. The decision of whether alignment of the tensile specimen is acceptable or not is based on a probabilistic analysis through the edge feature extraction of digital imaging. In order to verify the performance of the proposed system and investigate the effect of the misalignment of the specimen on tensile properties, the tensile tests were performed as displacement control in air and at room temperature for metal thin film, the beryllium copper (BeCu) alloys. In the case of the metal thin films, bending stresses caused by misalignment are insignificant because the films are easily bent during tensile tests to eliminate the bending stresses. And it was observed that little effects and scatters on tensile properties occur by stress gradient caused by twisting at in-plane misalignment, and the effects and scatters on tensile properties are insignificant at out-of-plane misalignment, in the case of the BeCu thin film.

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“…Micro-Electro-Mechanical systems (MEMS) have been studied for decades [1,2], with interest increasing recently because of growing commercial applications in many industrial fields such as electronic and magnetic devices and sensors [3]. Mechanical behavior especially fatigue damage plays an important role in determining the reliability of these systems [4][5][6]. Pure copper films are commonly used as MEMS materials where these films are bonded to the surface of steel plate by epoxy bonding or by diffusion [7].…”

Section: Introductionmentioning

confidence: 99%

Fatigue Damage Behavior Depending on the Bonding Interface Layer in Copper Film Bonded to Base Metals

Torii

Ishida²,

Hassan

et al. 2010

KEM

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Laminated copper films of the epoxy-bonded or diffusion-bonded to the base metal were used in order to investigate and analyze film fatigue behavior depending on the inevitable bonding interfaces for electric/functional parts used in MEMS. Fatigue damage was observed using SEM and crack initiation lives were evaluated at the notch root where the bonding interfaces could be observed directly through the thickness. These observations showed that the resin interface layer caused cracks without slips in a zig-zig pattern and also decreased fatigue crack initiation lives. On the other hand, fatigue damage was observed using an optical microscope on surface of the film with resin bonding or with diffusion bonded interfaces. In this case, many cracks were caused and propagated towards the width direction on the film bonded to the base steel with resin, while slip and cracks were caused along slip lines during fatigue on the film bonded to the base steel by diffusion. There was a significant difference in crack initiation behavior of the films between resin and diffusion bonded to base metals. This finding was not only for crack initiation site but also for roughness near the crack on the film. Using Eulerian equation of motion in continuum, this difference was discussed in terms of elastic displacement field with a wave caused from the base plate subjected to cyclic deformation. Such a wave motion enables us to understand the geometric effects of bonding interfaces on the fatigue damage behavior of the bonded film to base metal.

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Effect of Fabrication on High Cycle Fatigue Properties of Copper Thin Films

Cited by 7 publications

References 22 publications

Reliability design and assessment of a micro-probe using the results of a tensile test of a beryllium–copper alloy thin film

Reliability design and assessment of a micro-probe using the results of a tensile test of a beryllium–copper alloy thin film

Specimen alignment in an axial tensile test of thin films using direct imaging and its influence on the mechanical properties of BeCu

Fatigue Damage Behavior Depending on the Bonding Interface Layer in Copper Film Bonded to Base Metals

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