Open Access Short Research Article

Improving the Solder Joint Reliability Prediction Accuracy for Quad Flat No Lead Packages

Jefferson Talledo

Journal of Engineering Research and Reports, Page 81-89
DOI: 10.9734/jerr/2021/v20i717344

This paper discusses the modeling approach used in improving the solder joint reliability prediction for Quad Flat No Lead (QFN) packages. A new power equation fatigue prediction model was developed based on the accumulated creep strain energy density from FEA (finite element analysis) simulation and the corresponding actual experimental result in terms of solder characteristic life of different QFN packages. The new curve fitted fatigue life correlation equation was then used in the solder joint reliability modeling together with the use of a hyperbolic sine constitutive model for lead-free solder. The model prediction using the new curve fitted equation was compared with the result from using the equation previously published. Based on the results, the new curve-fitted life prediction equation was able to improve the accuracy of solder life prediction. This study shows that solder joint reliability prediction could be improved by developing a prediction model based on actual data and consistent FEA modeling considerations in terms of methodology, material model and properties.

Open Access Original Research Article

Occupational Health and Safety Management System and Organizational Performance in Selected Industries in Cross River State, Nigeria

U. K. Okeke, E. O. Nwaichi, J. N. Ugbebor

Journal of Engineering Research and Reports, Page 1-11
DOI: 10.9734/jerr/2021/v20i717336

The study adopted qualitative research design to examine Occupational Health and Safety Management System (OHSMS) implementation and organizational performance of Food/ Beverage and Building/Construction industries in Cross River State, Nigeria. Three companies from each category and 25 workers from each company totaling 150 research subjects were selected for the study. Three research questions and three null hypotheses were formulated to guide the study, while the internationally accepted OHSAS 18001 and ISO 45001 checklists, directed the preparation of a validated questionnaire which was used for data collection. Mean, standard deviation and Analysis of Variance were used for data analysis. Results showed significantly high and positive influence of OHSMS implementation on the performance of Food/ Beverage and Building/Construction industries in Cross River State. This stresses the strategic importance/need of OHSMS as a yard stick for organization and operation of every industry.  Comparatively however, a more significant influence of OHSMS implementation was recorded in Food/Beverage, indicating a difference in implementation level. Furthermore, each of all the OHSMS elements significantly influenced study industries, except for auditing, indicating that all the essential elements of OHSMS are important at every point of OHSMS implementation. However, more attention should be paid to auditing, in order to achieve a more reliable and successful implementation. In addition, OHSMS, with a consideration for local environment, was highly recommended for its application in all study industries, to bring about optimal performance in the areas of management influence and employee participation.

Open Access Original Research Article

Proactive Verification of Strip Y-Index to Mitigate Gross Misaligned Cut due to Mismatched Unit Pitching

Maria Virginia S. Buera, Mariane A. Mendoza, Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 12-19
DOI: 10.9734/jerr/2021/v20i717337

Shopfloor practices that when the first cut line was aligned with the hairline, actual blade cut, and saw street of the strip, the succeeding cut lines will automatically follow with the same alignment. Considering various factors that affect the condition of the strip, it was recommended to verify the succeeding cut lines of the strip to project if the hairline will still be aligned with the saw street as cutting goes on. Unfortunately, verification of succeeding cut lines was usually skipped and refer only with the first cut alignment as reference. Thus, end up risking the units for possible cutting misalignment. Cutting misalignment can be encountered when the programmed unit pitching measurement was mismatched with the actual unit pitch of the strip. However, mismatching of the unit pitch can be anticipated through y-indexing where the saw street of the strip will be verified for alignment with the hairline along the succeeding cut lines. Frequent occurrence of mismatched unit pitching was brought about by the strip condition after series of assembly processes that expands and retracts the strip. With the mentioned scenario which has been encountered from different semiconductor assembly plants, it was best to verify the y-indexing of the strip on top of verification on the first cut line alignment. Application of y-indexing verification is essential for the entrapment and correction of mismatched unit pitching. Rejection of units due to misaligned cuts can also be prevented. Assistance of operators to adjust and monitor the hairline to compensate the actual pitching was also avoided as early as first cut line verification.

Open Access Original Research Article

Geo-spatial Analysis of Farmland Affected by 2020 Flooding of River Rima, Northwestern Nigeria

Abdullahi Muktar, Sadiq A. Yelwa, Muhammad Tayyib Bello, Wali Elekwachi

Journal of Engineering Research and Reports, Page 20-27
DOI: 10.9734/jerr/2021/v20i717338

The flooding of River Rima is an annual issue affecting farmland located within the floodplains. This phenomena causes loss of farm produce and mass destruction of buildings, including roads and bridges in the area. Estimating the farmland affected by the flood will help the policy makers in decision making on how to mitigate the impact of flooding in the affected areas. The Terra/MODIS satellite image with 7-2-1 bands combination was used to classify the image into four landcover types. The area covered by flood was selected to calculate the flood area using Image Calculator module on QGIS software. The class of water was imposed on Digital Elevation Model that was obtained from Environmental Monitoring Satellite called The Shuttle Radar Topography Mission (SRTM). The result shows that River Rima flood occupies about 17,517 km2, equivalent to 1.7 million hectares of farmland that is below 230 meters (ASL). It was recommended that the local authorities and decision makers may use the flood map to showing flood risk zones so as to deter construction beyond the buffer. Farmers should adhere strictly to NiMet’s advice based on flood predictions. The civil engineers should also take note of the maximum water level during flooding so as to apply professional advice when constructing roads and bridges in the area.

Open Access Original Research Article

Full-annealing and its effect on the Mechanical Properties of Alloy 304H Stainless Steel

Anthony Edozie Onwudili, Sunday Chukwuka Iweka

Journal of Engineering Research and Reports, Page 28-44
DOI: 10.9734/jerr/2021/v20i717339

Stainless steel is an alloy of steel which contains at least 10.5% chromium, less than 1.2% carbon, and other alloying elements. It is widely used in many industries globally and their properties are highly influenced by their microstructure, heat treatment or by plastic deformation. But due to hardness, poor wear, and corrosion resistance, leading to short service life, there is need to investigate the effect of annealing on the mechanical properties of alloy 304H stainless steel and how the mechanical properties can be improved with a view of improving its service life and optimizing engineering usage. Sixteen (16) samples of the alloy were used. Twelve (12) samples were annealed at three different temperatures of 950oC, 1000oC and 1050oC inside a muffle furnace. At each temperature four samples were heat-treated inside the muffle furnace for 30 minutes. The result showed that the yield strength decreased from un-annealed sample to annealed samples at 950oC with a value of 504.8MPa and increased at 1000oC with a value of 610MPa and a decrease of 323.8 MPa was obtained at 1050oC. Also, the ultimate tensile strength showed an increase from   950oC with a value of 826.3MPa to 1000oC with a value of 930MPa but there was a slight decrease at 1050oC for all samples. The ultimate tensile strength at 1000oC with a value of 930MPa was the highest in all the samples. The annealed samples at 1000oC had the highest percentage elongation of 13.57% which shows an increase in the ductility of the material. The hardness of the material decreased from 157.25 BHN at 950oC to 134.00BHN at 1000oC. An increase to 169.50BHN was however obtained at 1050oC. Thus, full-annealing of alloy 304H stainless steel at 1000oC increases in ductility as hardness decreases.

Open Access Original Research Article

Off-centered Ball Resolution Through Multi-hole Process Plate Implementation at Wirebond Process

J. Pulido, F. R. Gomez, E. Graycochea Jr.

Journal of Engineering Research and Reports, Page 45-50
DOI: 10.9734/jerr/2021/v20i717340

With the continuous trend of new technologies in semiconductor manufacturing assembly, challenges and issues are unavoidable. This paper presents the modification and improvement done on the process plate design to eliminate the bouncing effect of the silicon die that leads to off-centered ball (OCB) reject during the formation of wire on a quad flat no-leads (QFN) device. The panel type single-row process plate cannot totally vacuum the warped leadframe and this is resulting to off-centered ball. Through changing the panel type single-row process plate to panel type multi-hole process will have a strong vacuum sucked underneath the leadframe and eliminates the occurrence of off-centered ball. Future works could use the improved process plate design for devices of similar configuration.

Open Access Original Research Article

Maximizing the Process Capability of Singulation Machine by Dual Work Piece Cutting on Circular Tape Frame

Mariane Mendoza, Maria Virginia Buera, Frederick Ray Gomez

Journal of Engineering Research and Reports, Page 51-55
DOI: 10.9734/jerr/2021/v20i717341

Tape saw singulation is the process where a strip was mounted on the tape attached on the frame and then sawn into single units. Circular tape saw singulation only caters one panel of the two-paneled strip which was found to be consuming with the machine capacity and resources. Driven by continuously growing volumes of customer demands at the Philippines for the past two years, it was a challenge for the machine to maximize its capacity while minimizing the cost and resources. Opportunity was found on exploring the idea of dual work piece where two strip panels were catered by one circular tape frame. Dual work piece application would not only maximize the machine capability and capacity but also reduce the cost of resources consumed per strip loading. In this study, the authors have explored the workability of dual work piece cutting where two panels can be catered on one circular frame instead of the current one panel per circular frame. Dual Work Piece application was found to be effective to achieve the goal of maximizing the machine capacity while trimming down the expenses by 50% that was brought about by the resources demanded to process the strips at singulation. With the results of the study, it was recommended for the dual work piece cutting be applied and explored on growing semiconductor industry.

Open Access Original Research Article

Influence of Fiber Properties on Harmonic and Intermodulation Distortions of Semiconductor Lasers

Moustafa Ahmed, Yas Al-Hadeethi, Ghodran Alghamdi

Journal of Engineering Research and Reports, Page 56-67
DOI: 10.9734/jerr/2021/v20i717342

This paper introduces modeling and simulation of the harmonic and intermodulation distortions of semiconductor laser radiating an optical fiber link. The study is based on the rate equation model of semiconductor lasers excited by injection current with two sinusoidal tones separated by a radio frequency. The modulated laser signal is modeled in both the time and frequency domains. The laser signal distortions include the 2nd and 3rd harmonic distortion (2HD and 3HD), and the third-order intermodulation distortion IMD3. The laser is assumed to be modulated around its relaxation frequency. Influence of the modulation depth on the signal distortion is investigated when the laser is free running and when it is radiating a fiber link. In the latter case, influences of the attenuation and chromatic dispersion on the signal dispersion are elucidated when the fiber length increases up to 10 km. The results show that the fiber attenuation does not affect the signal distortion, whereas the chromatic dispersion affects both the harmonic distortions and intermodulation distortion. Sending the laser signal down an optical fiber of length ~ 5km can help in minimizing 2HD which is the dominant harmonic distortion of the modulated signal. This range of optical fiber is also characterized with intermodulation distortion less than 0dBc.

Open Access Original Research Article

Laser DAF Cut: A Breakthrough Approach of Die Attach Film Singulation for Thin Wafers

Aiza Marie E. Agudon, Frederick P. Arellano, Bryan Christian S. Bacquian

Journal of Engineering Research and Reports, Page 68-80
DOI: 10.9734/jerr/2021/v20i717343

Today, semiconductor world is becoming more inclined to thinner Integrated Circuit (IC) packages. IC packages will require thinning of the internal configuration of the package, which involves the die or the wafer and the adhesive material, which is the Die Attach Film (DAF). Aligned to this, as wafers goes thinner it becomes more of a challenge in process development especially during its preparatory stages, such as wafer back grinding and sawing processes. As the die becomes smaller and thinner wafer sawing process should have minimum effect on the mechanical integrity of the silicon so as not to alter its quality.

New technologies were introduced so as to adopt to this development trend, one of this is the Dicing Before Grinding (DBG). Compared to the normal wafer preparation process that is wafer back grinding before wafer sawing, DBG flow is wafer sawing first prior wafer back grinding processes. The application of DBG technology eliminates the mechanical draw backs of the conventional wafer sawing process. In addition, with the use of DAF for thinner packages, DBG was developed together with the Die Attach Film (DAF) cutting solution, which is Laser DAF Cutting.  DAF are separated using Laser as a cutting medium to address potential processability problems that may occur on the conventional mechanical blade saw.

The paper discuss the Laser DAF cut development that covers the Design of Experiments (DoE) to understand the different characteristics of Laser DAF solution and be validated through actual simulation and wafer processing. The paper will also cover the interaction of different DAF thicknesses and Laser DAF parameters in order to define the critical characteristics so as to understand the behavior of different laser DAF parameters in achieving optimal DAF cutting process responses.

Open Access Original Research Article

Experimental Design of Physical Unconfined Aquifer for Evaluation of Well Abstraction Effects: Laboratory Approach

Dak Bahadur Khadka

Journal of Engineering Research and Reports, Page 90-102
DOI: 10.9734/jerr/2021/v20i717346

In unconfined aquifer water flows in both horizontal and vertical direction when pumping. So its study during pumping action is more complex. Soil type, porosity, hydraulic conductivity and transmissivity are important parameters that control the specific yield, drawdown and radius of influence on aquifer while abstraction. Due to large extraction of water from the aquifer, the water table drops down and may lead to permanent depletion of yield capacity of aquifer. For practical understanding of water being pumped from aquifer and its impacts on water storage the easiest method is experimental approach .So therefore, this study was planned to carry out the well abstraction from unconfined aquifer of homogeneous sandy soil designed as physical model on rainfall simulator at hydraulic laboratory hall of Campus itself. The catchment dimension is 2.2 meter length, 1 meter width and 0.15 meter depth with impermeable base filled with fine sand as per specification. The simulator was adjusted to make horizontal aquifer. The experimental observations were carried out in two conditions, first was well abstraction with no rainfall after saturation and the second is with rainfall even after saturation condition obtained. The two wells were operated for the abstraction of water simultaneously so that the effect of one well to another could be studied. After observation and data collection, for the analysis of hydraulic conductivity Dupit model. Empirical model and relative effective porosity model (REPM) were used for the comparative study. Similarly the radius of influence was estimated by three models (weber,Kusakin and Sichardt).  For the estimation of transmissivity of the aquifer Thien model was used. Also the general equation (product of hydraulic conductivity and depth of aquifer) was used. Study showed the suitability of the available theories and governing equations for unconfined aquifer. The most important part of the study was to establish the correlation of drawdown and radius of influence with the time period of well abstraction. From the results the correlation coefficient for time and drawdown was of 90% and for time and radius of influence was 97%.

Open Access Original Research Article

Gis-Based Multi Criteria Model for Location of Rice Aggregation Centers in Anambra State

C. D. Okpala, J. I. Igbokwe, C. O. Nwajinka, E. C. Igbokwe, J. I. Ubah

Journal of Engineering Research and Reports, Page 103-116
DOI: 10.9734/jerr/2021/v20i717347

Rice aggregation centers are tasked with checkmating substandard agricultural produce that are often encountered by the integrated millers during the course of buying from farm to farm to ensure already made market for their produce. Thus, it must be well placed to occupy strategic positions such that all different rice cultivating zones of the state get access to the facility. Given that these facilities will provide salient services, sets of demand points tasked with the provision storage, processing capability and a constant market for various rice farmers within the state. It is pertinent that these facilities are located properly considering all unique factors on ground. This study therefore aimed at a GIS-based multi criteria model for location of rice aggregation centers in Anambra State. The study was carried out using Geographical Information System (GIS) technology. Several GIS thematic layers were obtained and considered important factors in citing rice aggregation centers such as road network, Land Use and Land Cover (LULC), slope, river, cost distance, electricity network, floodplains, erosion plains and proximity to rice farms. It revealed optimal locations for siting a modular aggregation rice center at Nzam, Onoia, Aguleri, Nando, Akenu, Achalla, Ezira, Ndiokpalaeze, Ogbakuma and Uli. The goal throughout this study was to provide a reliable and complete analysis of siting modular rice aggregation centers in the agricultural zones in Anambra State. The approach and results obtained in this study are recommended as a spatial decision tool for site selection of modular rice aggregation centers in developing countries.

Open Access Original Research Article

Utilization of the Karnaugh Map in Exploring Cause-effect Relations Modeled by Partially-defined Boolean Functions

Ali Muhammad Ali Rushdi, Raid Salih Badawi

Journal of Engineering Research and Reports, Page 117-137
DOI: 10.9734/jerr/2021/v20i717348

This paper utilizes a modern regular and modular eight-variable Karnaugh map in a systematic investigation of cause-effect relationships modeled by partially-defined Boolean functions (PDBF) (known also as incompletely specified switching functions). First, we present a Karnaugh-map test that can decide whether a certain variable must be included in a set of supporting variables of the function, and, otherwise, might enforce the exclusion of this variable from such a set. This exclusion is attained via certain don’t-care assignments that ensure the equivalence of the Boolean quotient w.r.t. the variable, and that w.r.t. its complement, i.e., the exact matching of the half map representing the internal region of the variable, and the remaining half map representing the external region of the variable, in which case any of these two half maps replaces the original full map as a representation of the function. Such a variable exclusion might be continued w.r.t. other variables till a minimal set of supporting variables is reached. The paper addresses a dominantly-unspecified PDBF to obtain all its minimal sets of supporting variables without resort to integer programming techniques. For each of the minimal sets obtained, standard map methods for extracting prime implicants allow the construction of all irredundant disjunctive forms (IDFs). According to this scheme of first identifying a minimal set of supporting variables, we avoid the task of drawing prime-implicant loops on the initial eight-variable map, and postpone this task till the map is dramatically reduced in size. The procedure outlined herein has important ramifications for the newly-established discipline of Qualitative Comparative Analysis (QCA). These ramifications are not expected to be welcomed by the QCA community, since they clearly indicate that the too-often strong results claimed by QCA adherents need to be checked and scrutinized.

Open Access Original Research Article

Pattern Recognition System Program Advancement to Compensate Strip Expansion on 1-Map Strips

Maria Virginia S. Buera, Mariane A. Mendoza, Frederick Ray I. Gomez

Journal of Engineering Research and Reports, Page 138-143
DOI: 10.9734/jerr/2021/v20i717349

Package singulation process is where the whole strip was sheared to produce individual units. Existing singulation program for 1-map strip have only six (6) pattern recognition system (PRS) points along the whole strip with 240 mm length. Considering the length of the strip, it is prone with misalignment especially when the unit pitching is small. Due to a big gap of PRS points, the compensation of unit pitch has a significant variable value due to strip expansion that results to misalignment when not monitored. PRS works to calculate and compensate the appropriate alignment of the strip including the unit pitching. Distance between adjacent PRS points divided by the number of cut lines it covers results to the unit pitch. The lesser accumulation of strip expansion, the more it compensates and align with the actual unit pitch. Modification of PRS Program to add PRS points along the strip in order to lessen the distance between adjacent PRS points were made and results were promising compared with the existing with only 6 PRS points. It has been found out that unit pitch varies by adding PRS points that will compensate the expansion of the whole strip.

Open Access Original Research Article

Backside Chippings Improvement through Wafer Dicing Parameter Optimization and Understanding the Anistropic Silicon Properties

Aiza Marie E. Agudon, Bryan Christian S. Bacquian

Journal of Engineering Research and Reports, Page 144-152
DOI: 10.9734/jerr/2021/v20i717350

Semiconductor Companies and Industries soar high as the trend for electronic gadgets and devices increases. Transition from “manual” to “fully automatic” application is one of the advantages why consumer adapt to changes and prefer electronic devices as one of daily answers. Individuals who admire these electronic devices often ask how they are made.

As we look inside each device, we can notice interconnected microchips commonly called IC (Integrated Circuit). These are specially prepared silicon wafers where integrated circuit are developed. Commonly, each device is composed of numerous microchips depending on the design and functionality

IC production is processed from “front-end” to “back-end” assembly. Front-end assembly includes wafer fabrication where electrical circuitry is prepared and integrated to every single silicon wafers. Back-end assembly covers processing the wafer by cutting into smaller individual and independent components called “dice”. Each dice will be placed into Leadframe, bonded with wires prior encapsulating with mold compounds. After molding, each IC will be cut through a process called singulation. Afterwards, all molded units are subjected for functional testing.

Dice is central to each IC; it is where miniature transistor, resistor and capacitor are integrated to form complex small circuitry in microchips.

Pre-assembly (Pre-assy) stations have the first hand prior to all succeeding stations. Live wafers are primary direct materials processed in these stations. Robust work instruction and parameter must be practiced during handling and processing to avoid gross rejection and possible work-related defects.

The paper is all about the challenges to resolve and improved the backside chippings in 280um wafer thickness in mechanical dicing saw. The conventional Mechanical dicing process induce a lot of mechanical stress and vibration during the cutting process which oftentimes lead to backside chipping and die crack issues. However, backside chippings can mitigate with proper selection of parameter settings and understand the silicon wafer properties.

Open Access Original Research Article

Elimination of Intermetallic Coverage Over-etching on Aluminum Pad

Jonalyn Jaylo-Sia, Jonathan Pulido, Frederick Ray Gomez

Journal of Engineering Research and Reports, Page 153-156
DOI: 10.9734/jerr/2021/v20i717351

Intermetallic coverage (IMC) is one of the critical wirebond output responses that is usually checked to ensure the ball to pad integrity. The success of wirebonding relies on the formation of an interfacial intermetallic growth of ball bond to ensure it can withstand reliability stresses. The challenging approach in IMC analysis detect as over-etching around IMC area that leads to inaccurate IMC data collection. To address the over-etching, we generate a new method which is backside polishing that results to a reliable IMC data collection and help reduced the cycle time of IMC data gathering.