Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Microelectronics and Packaging Society
Journal Basic Information
Journal DOI :
The Korean Microelectronics and Packaging Society
Editor in Chief :
Volume & Issues
Volume 8, Issue 4 - Dec 2001
Volume 8, Issue 3 - Sep 2001
Volume 8, Issue 2 - Jun 2001
Volume 8, Issue 1 - Mar 2001
Selecting the target year
COG(chip-on-glass) Mounting Using a Laser Beam Transmitting a Glass Substrate
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 1~10
Chip-on-glass(COG) mounting of area array electronic packages was attempted by heating the rear surface of a contact pad film deposited on a glass substrate. The pads consisted of an adhesion (i.e. Cr or Ti) and a top coating layer(i.e. Ni or Cu) were healed by the UV laser beam transmitted through the glass substrate. The lather energy absorbed on the pad raised the temperature of a solder ball which is in physical contact with the pad, and formed a reflowed solder bump. The effects of the adhesion and top coating layer on the laser reflow soldering were studied by measuring temperature profile of the ball during the laser heating process. The results were discussed based on the measurement of reflectivity of the adhesion layer. In addition, the microstructures of solder bumps and their mechanical properties were examined.
Wafer Level Hermetic Sealing Characteristics of RF-MEMS Devices using Non-Conductive Epoxy
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 11~15
In this paper, hermetic sealing technology was studied for wafer level packaging of the RF-MEMS devices. With the flip-chip bonding method. this non-conductive B-stage epoxy sealing will be profit to the MEMS device sealing. It will be particularly profit to the RF-MEMS device sealing. B-stage epoxy can be cured by 2-step and hermetic sealing can be obtained. After defining 500
-width seal-lines on the glass cap substrate by screen printing, it was pre-baked at
for about 30 minutes. It was, then, aligned and bonded with device substrate followed by post-baked at
for about 30 minutes. By using this 2-step baking characteristic, the width and the height of the seal-line could be maintained during the sealing process. The height of the seal-line was controlled within
in the 4 inches wafer and the bonding strength was measured to about 20MPa by pull test. The leak rate, that is sealing characteristic of the B-stage epoxy, was about
cc/sec from the leak test.
Sensitivity Improvement of 3-D Hall Sensor using Anisotropic Etching and Ni/Fe Thin Films
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 17~23
The 3-D Hall sensor has two horizontal magnetic field sensing parts (
, y components) and one vertical magnetic field sensing part (z component). For conventional, 3-D Hall sensor it is general that the sensitivity for
is about 1/10 compared with those for
. Therefore, in this work, we proposed 3-D Hall sensor with new structure. We have increased the sensitivity about 6 times to form the trench using anisotropic etching. And we have increased the sensitivity for the
by 80% compared with those of
using deposition of the ferromagnetic thin films on the bottom surface of the wafer to concentrate the magnetic fluxes. When the input current was 3 mA, sensitivities of the fabricated sensor with Ni/Fe film for
were measured as 120.1 mV/T, 111.7 mV/T, 95.3 mV/T, respectively. The measured linearity of the sensor was within
3% of error.
Creep Properties of Sn-3.5Ag-xBi Solders
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 25~33
Sn-3.5Ag-xBi alloys with five different levels of Bi (0, 2.5, 4.8, 7.5, 10 wt%) were prepared for evaluating creep properties. Cast alloys were roiled and heat treated to provide stable microstructures during the subsequent creep tests, which were conducted under constant load using dog-bone specimens. For the Bi containing alloys, creep strength showed the maximum around 2.5 wt%Bi and tended to decrease with increasing Bi content. The stress exponent of the alloy was around 4, suggesting typical dislocation creep, but the exponent was 2 for the 10 wt%Bi alloy, suggesting creep assisted by grain boundary Sliding. For the Bi containing alloys, the brittle fracture mode appeared showing small amount of reduction of area, while the ductile fracture mode was true for the Bi free alloy. Microstructural examination of ruptured specimens showed cavitations on grain boundaries normal to the load axis, and a significant of grain boundary sliding for the Bi containing alloys.
A Study on the Optimal Shape Prediction of
BGA Solder Joints
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 35~41
In this paper, several methods to predict the solder joint shape are studied. Although there are various methods to predict the solder joint shape, such as truncated sphere method. force-balanced analytical solution, and energy-based methods like surface evolver developed by Ken Brakke, we calculate solder joint shape of
BGA by two solder joint shape prediction methods(truncated sphere method and surfaceevolver) and then compare results of each method. The results indicate that two methods can accurately predict the solder Joint shape in an accurate range. After that, we calculate reliability solder joint shape under thermal cycle test by FEA program ANSYS(version 5.62). As a result, it could be found that optimal solder joint shape calculated by solder joint prediction method has best reliability in thermal cycle test.
Micromachining & Optical Properties of Li
Glass System by Laser Treatment
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 43~45
For photosensitive and micro-structuring in
glasses by laser treatment, Nd:YAG laser in 355 nm and 1064 nm wavelength was irradiated to the glass to investigate fracture characterization and optical changes. The fractured glass surfaces irradiated by 1064 nm laser was observed by Scanning Electron Microscope(SEM) and optical microscope, and optical changes caused by 355 nm later was identified from absorption spectra. In this study, it could be expected that the laser treatment technology will be utilized for 3-dimensional micro-structure, internal waveguide, optical memory by optical absorption changes in glass matrix.
A Study on the Implementation of Wave Soldering Process and the Solder Joint Reliability Using Sn-Cu-Ni Lead-free Solder
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 47~52
Pb-free wave soldering process of AC Adapter was implemented by six sigma method using Sn-Cu-Ni type solder. The solder joint appearance, microstructural change, a lift-off phenomenon and reliability were evaluated through thermal shuck test.
-type intermetallic compound of which thickness is about 5
was found at solder joint between Sn-Cu-Ni solder and copper land. After applying the thermal shock test of as-soldered product up to 750 cycles, no crack was fecund at the solder joint. The newly developed product was superior to conventional one in terms of productivity and reliability.
A Study on Intelligent Generator of Mold Temperature Using Fuzzy Algorithm to Prevent Short Shot
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 53~57
A short shot is an incomplete molded part caused by insufficient material injection into the mold. Remedial actions to control the process conditions can be taken by injection molding experts based on their knowledge and experiences. However, it is very difficult for non-experts to avoid short shot by finding the proper process conditions such as mold temperature, melt temperature and filling time. In this paper, an intelligent generator of optimal process conditions based upon fully logic algorithm is proposed so that trial and error can be minimized and non-experts an well at experts can also find the optimal process conditions.
Study on the Epoxy/BaTiO
Embedded Capacitor Films for PWB Applications
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 59~65
composite capacitor films with excellent stability at room temperature, uniform thickness, and electrical properties over a large area ware successfully fabricated. The composite capacitor films with good film formation capability and easy process ability were made from epoxy resin developed for ACF as a matrix and two kinds of
powders as fillers to increase the dielectric constant of the composite film. The crystal structure of the powders and its effects on dielectric constant of the films were investigated by X-ray diffraction (XRD). And the optimum amount of dispersant, phosphate ester, was determined by viscosity measurement of suspension. DSC and dielectric property tests were conducted to decide the right curing temperature and the optimum amount of the curing agent. As a result, the capacitors of 7
thick film with 10 nF/
and low leakage current were successfully demonstrated.
Flow Analysis and Process Conditions Optimization in a Cavity during Semiconductor Chip Encapsulation
Journal of the Microelectronics and Packaging Society, volume 8, issue 4, 2001, Pages 67~72
An Effort has been made to more accurately analyze the flow in the chip cavity, particularly to model the flow through the openings in the leadframe and correctly treat the thermal boundary condition at the leadframe. The theoretical analysis of the flow has been done by using the Hele-Shaw approximation in each cavity separated by a leadframe. The cross-flow through the openings in the leadframe has been incorporated into the Hele-Shaw formulation as a mass source term. The optimization program based on the complex method integrated with flow analysis program has been successfully used to obtain the optimal filling conditions to avoid short shot.